After you rename the .aif files to .wav, will the .wav's play in Foobar2000 (more lightweight) or Winamp (more graphics)? Both of these media players are free. That would be a sign that the problem is not with the .wav's. I just renamed a 16 bit .wav that was on my computer to .aif, and it played fine with Windows Media Player, so I assume it works the other way as well. I don't think WMP will play 24 bit .wav files unless you have a 24 bit capable sound card. Winamp or Foobar2000 will play 24 bit files even if you don't have a 24 bit soundcard.

Then, I would put all the wavs from one show into Trader's Little Helper, select "audio file details." In "len mode," click "show details" If there are any sector boundary errors or header errors, this will be displayed. Fix any errors if necessary. Then encode to FLAC.

Or in FLAC frontend, set the level to 8, check "verify" box, check "align on sector boundaries" box. Set output directory the same as the input directory, then hit "encode" FLAC frontend might have a problem if there are specific header issues I think. Try TLH if you have problems.

It is important to put all the wavs from one show into TLH or FLAC Frontend when sector boundaries will be fixed because a little bit of silence (a fraction of a second) will be added to the end of the last file usually. If they are done individually or a few at a time, silence will be added to the end of the last file and your show will not be seamless, it will have slight pauses between tracks.