What tool(s?) did you use to extract the Zip/RAR files? Does it support subdirectories? The PSF format supports putting the LIB files in a different directory (than the xSF files), and it's possible that when you extracted the files, the LIB files didn't end up where the xSF files expected them to be. Most sets are set up to have the LIB and xSF files in the same directory, but there are a few that do it differently.
Can you provide specific file names of the files that do, and don't play, and in what set? Mostly, I'm looking for examples. It'd be useful, to try and narrow down what the problem might be. It'd be even more useful, if you can view the "RAW" tags, and see how the LIB files are being called/addressed (as in, what the tags look like).
To me, it sounds more like the LIB files are being called/addressed improperly, and thus, the files aren't playing. While my memory tells me there are programs to "combine" the LIB and xSF files together (to get rid of minixSF), I don't remember what they are, or how to use them. Not to mention that, really, there's not any especially good reason to do so. Try playing the xSF files from the original RAR/ZIP file, and see if that works. If it does, then there's most likely a problem with your extraction method. If they don't work, then it sounds like there's more going on, and therefore "we" would need more information to figure out what it might be.
Anyway, answering those questions (in the paragraphs above) would be helpful. Hopefully my post is beneficial, and you get this problem solved. Mouser X over and out.
For extracting RAR files, I use Winrar, and for extracting ZIP files, I just use Windows Explorer (opening the ZIP and clicking Extract All Files), but they're all extracted to the same folder.
For the Crash Team Racing example, there are a number of different PSFLIBs. The main one is ctr.psflib, which most of the files are read from, and they all work in Foobar. There are 3 others, dingo.psflib, map.psflib, and intro.psflib, and the Intro tracks, Map tracks and Dingo Canyon track which obviously have data in these don't work in Foobar (although they do in Winamp).
Crash 2 has 9 separate psflib files and Crash 3 has 7 but all the tracks included there work in Foobar. Crash 1 is just normal PSF files and they all work perfectly, so I don't know if there's anyway of converting the versions with psflibs back into PSF files like that if that would make it easier to move them around.
I also downloaded a number of GBA (GSF) audio files though, Kuru Kuru Kururin, Pokemon Fire Red/Leaf Green, Pokemon Ruby/Sapphire, Pokemon Emerald, and I think there would have been more, except all of these use minigsf and gsflib format, and I haven't managed to get any of those tracks working yet, although that might be due to a plugin issue, as I've just realised that I'm not sure my plugins at the moment cover that format.
Anyway, I just tried the suggestion of playing the Crash Team Racing files straight from the ZIP file, and interestingly the same thing happened. The files that worked before worked, and the files that there were problems with still didn't. If you want to try yourself, I've been using Zophar's Domain to download most of the files, although I think I found alternative downloads elsewhere that had the same issue.
Heh, I didn't realised this has slipped so far back in the pages. Did anyone manage to figure out a solution to the problems I was having, as I haven't carried on with arranging them since. Thanks.