Looking for help. I'm fairly new to Vegas. I got Vegas 4 from a friend who prefers Premier. I've only ever used Pinnacle Studio before so I'm on a bit of a learning curve. Things were progressing slowly but smoothly until I tried to encode to mpeg. I already had Main Concept mpeg Encoder installed on my pc and did not think I'd need the plug-in for Vegas 4. But when I tried to encode an avi to mpeg, Vegas 4 says I need to purchase the plug-in. The Main Concept encoder wasn't on the list of available codecs when trying to render so I tried to activate it using my existing Main Concept serial number but without success. Now when I try to edit any video file in Vegas I get an error message saying that there was an error during playback and that I'm trying to play an unsupported media type. In detail, its states-

The playback device Modem #0 Line Playback does not support the current output format. The playback device Modem #0 Line Playback does not exist.

Can anyone help? At the moment I can't do anything in Vegas 4.