> When I render an .avi either with the NTSC DV codec or the Default Uncompressed codec...the .avi file will not playback. I get an error message and the program terminates...any ideas?

What program terminates? Screenblast? What is the error message? It sounds like your having a problem with the DV codec on your machine.

> Also...I downloaded Virtual Dub...is there a simple explanation about the benefits of using this program and how you use it? I must be stupid because I can't figure out how to use it....thanks

VirtualDub is a program for processing video with various filters. The basic steps are as follows:

Step 1: Use File->Open video file... (ctrl-O) to open the AVI file that you want to process.
Step 2: Use the Video->Filters... menu to add the filters you want to apply. (I use it to apply the Dynamic Noise Reduction 2.1 filter to any analog footage I capture to clean up the analog noise).
Step 3: After you apply your filters use the Video->Compression... menu item to select the CODEC you want to use to save it.
Step 4: Finally use File->Save as AVI (F7) to process your video and save the results.

If you have a bunch of files to process there is a batch mode where you queue up the jobs and then run them all at once.

~jr