There are several Vegas scripts that have the word "batch" in their title, but they each do different things. I think the one you are using is designed to take a single project and render it multiple times using several different templates.

If what you want to do instead is take a whole bunch of .VEG files (Vegas project files) and render each project without any further operator intervention, then you want a different script. The two that SoFo/Sony provides on their dowload page won't do the trick.

You can try this basic script (although you have to edit it to specify your files and directory):

RenderQueue.js

I tried to find a link to the script file I use for batch rendering. I can't find it anymore. Therefore, here is the contents of that script. Just cut and paste it to a file, and give that file the extension ".js".
-------------------

/**

 * This script renders media files found in an input directory using a

 * single render template and saves the results in an output

 * directory.  To change the input directory, output directory, and

 * render template, edit the variables below.

 *

 * NOTE!!! This script requires Vegas 4.0c.

 *

 * Revision Date: May 01, 2003.

 **/



import System;

import System.Text;

import System.IO;

import System.Windows.Forms;

import SonicFoundry.Vegas;



// The inputDirectory variable specifies where the rendered files will

// be created (do not include the trailing back-slash)

var inputDirectory = "D:\\video";



// The outputDirectory variable specifies where the rendered files

// will be created (do not include the trailing back-slash)

var outputDirectory = "D:\\renders";



// The rendererRegexp and templateRegexp variable are regular

// expressions used to match renderer file type names and template

// names.

var rendererRegexp = /RealMedia 9/;

var templateRegexp = /256 Kbps Video/;



// The inputFileRegexp is used to filter the input files. Only those

// whose file name matches using this regular expression will be

// converted. The following will match all files the end with avi

// (ignoring case):

var inputFileRegexp = /.avi$/i;



// This version will match all input files.

//var inputFileRegexp = /.*/;



// The overwriteExistingFiles variable determines whether or not it is

// OK to overwrite files that may already exist whose name is the same

// as ones created by running this script.  For safety, the default is

// false.  Set the variable to true to allow overwrites.

var overwriteExistingFiles = false;





try {



    // make sure the output directory exists

    if (!Directory.Exists(inputDirectory))

    {

        var msg = new StringBuilder("The input directory (");

        msg.Append(outputDirectory);

        msg.Append(") does not exist.\n");

        msg.Append("Please edit the script to specify an existing directory.");

        throw msg;

    }



    // make sure the output directory exists

    if (!Directory.Exists(outputDirectory))

    {

        var msg = new StringBuilder("The output directory (");

        msg.Append(outputDirectory);

        msg.Append(") does not exist.\n");

        msg.Append("Please edit the script to specify an existing directory.");

        throw msg;

    }



    var renderer = FindRenderer(rendererRegexp);

    if (null == renderer) {

        throw "Failed to find renderer";

    }



    var renderTemplate = FindRenderTemplate(renderer, templateRegexp);

    if (null == renderTemplate) {

        throw "Failed to find render template";

    }



    var newExtension = renderer.FileExtension.substring(1);



    // create a new project with one video track and one audio track.

    var proj = new Project();



    var videoTrack = new VideoTrack();

    proj.Tracks.Add(videoTrack);



    var audioTrack = new AudioTrack();

    proj.Tracks.Add(audioTrack);



    // save the new project to the output directory 

    //Vegas.SaveProject(Path.Combine(outputDirectory, "temp.veg"));



    // enumerate the files in the input directory

    var fileEnum = new Enumerator(Directory.GetFiles(inputDirectory));

    while (!fileEnum.atEnd()) {

        var inputFile = fileEnum.item();



        // skip files that don't end with the right extension

        if (null == inputFile.match(inputFileRegexp)) {

            fileEnum.moveNext();

            continue;

        }



        // skip files that are not valid media files.

        var media = new Media(inputFile);

        if (!media.IsValid()) {

            fileEnum.moveNext();

            continue;

        }



        var videoStream = media.Streams.GetItemByMediaType(MediaType.Video, 0);

        var audioStream = media.Streams.GetItemByMediaType(MediaType.Audio, 0);



        // if needed, add a video event and associate video stream

        if (null != videoStream) {

            var videoLength = videoStream.Length;

            var videoEvent = new VideoEvent(new Timecode(), videoLength);

            videoTrack.Events.Add(videoEvent);

            var videoTake = new Take(videoStream);

            videoEvent.Takes.Add(videoTake);

        }



        // if needed, add a audio event and associate audio stream

        if (null != audioStream) {

            var audioLength = audioStream.Length;

            var audioEvent = new AudioEvent(new Timecode(), audioLength);

            audioTrack.Events.Add(audioEvent);

            var audioTake = new Take(audioStream);

            audioEvent.Takes.Add(audioTake);

        }



        var outputFileName = Path.GetFileNameWithoutExtension(inputFile) + newExtension;

        var outputPath = Path.Combine(outputDirectory, outputFileName);



        var status = DoRender(outputPath, renderer, renderTemplate);

        if (status == RenderStatus.Canceled) {

            // may want have a dialog here allowing user to

            // continue with remaining files.

            break;

        } else if (status != RenderStatus.Complete) {

            throw "Failed on input file: " + inputFile;

        }



        // clean up the project.

        videoTrack.Events.Clear();

        audioTrack.Events.Clear();

        proj.MediaPool.Remove(inputFile);



        fileEnum.moveNext();

    }



} catch (e) {

    if (!e.skipMessageBox)

        MessageBox.Show(e);

}



// Perform the render.  The Render method returns a member of the

// RenderStatus enumeration which is, in turn, returned by this

// function.

function DoRender(fileName, rndr, rndrTemplate) {

    ValidateFileName(fileName);



    // make sure the file does not already exist

    if (!overwriteExistingFiles && File.Exists(fileName)) {

        throw "File already exists: " + fileName;

    }



    // perform the render.  The Render method returns

    // a member of the RenderStatus enumeration.  If

    // it is anything other than OK, exit the loops.

    //var status = Vegas.Render(fileName, rndrTemplate);

    var status = Vegas.Render(fileName, rndrTemplate);

    return status;

}



function ValidateFileName(fileName : System.String) {

    if (fileName.length > 260)

        throw "file name too long: " + fileName;

    var illegalCharCount = Path.InvalidPathChars.Length;

    var i = 0;

    while (i < illegalCharCount) {

        if (0 <= fileName.IndexOf(Path.InvalidPathChars[i])) {

            throw "invalid file name: " + fileName;

        }

        i++;

    }

}



function FindRenderer(rendererRegExp : RegExp) : Renderer {

    var rendererEnum : Enumerator = new Enumerator(Vegas.Renderers);

    while (!rendererEnum.atEnd()) {

        var renderer : Renderer = Renderer(rendererEnum.item());

        if (null != renderer.FileTypeName.match(rendererRegExp)) {

            return renderer;

        }

        rendererEnum.moveNext();

    }

    return null;

}



function FindRenderTemplate(renderer : Renderer, templateRegExp : RegExp) : RenderTemplate {

    var templateEnum : Enumerator = new Enumerator(renderer.Templates);

    while (!templateEnum.atEnd()) {

        var renderTemplate : RenderTemplate = RenderTemplate(templateEnum.item());

        if (null != renderTemplate.Name.match(templateRegExp)) {

            return renderTemplate;

        }

        templateEnum.moveNext();

    }

    return null;

}