Might want to post this somewhere like doom9.org where perhaps more folks have experience with & use the lame codec. Otherwise, may be incompatible with Vegas, which is set up to use it's own encoder... Might help to check the FAQ here: http://www.nwlink.com/~zachd/ , reading info on multiple mp3 codec files installed, prob and cures - might be a conflict there that lame is getting into the middle of.