These errors tell me that you just dropped the media into DVDA and expected DVDA to recompress for the disc.
Since one of the errors says the bitrate is too low, then the media is probably AVCHD. (I’ve never seen other formats generate this error, but that doesn’t mean they won’t).
Are you making a DVD or Blu-Ray disc?
Either way, make the DVDA compliant files in Vegas using the DVD Architect presets then DVDA won’t have to recompress anything.
Steve Mann
MannMade Digital Video
http://www.mmdv.com