Audio skipping

[Vucious Creed]

I'm pretty sure someone has already asked something like this, but I had to ask anyway to make sure... just in case no one else had done so.  I am using the in_spc plug-ins (SNESAmp, obviously) to play SNES audio files, but the problem is that all of the tracks that support said files are skipping and/or scratching horribly.  I have similar problems with .usf audio files.

Can someone tell me what I can do to get the .spc/.usf files to play more smoothly without any sort of audio distortion?