Ahhh right.
What mp3 codecs are installed on the system, that's all I can think of....OR.....that there may be some extraneous, non-standard data, within the files.
I would suggest you try decoding them to .wav first, this will firstly tell you that the tunes therein are OK, and also the change of format will in itself remove any unwanted baggage in the files. No idea what the best tool for that is in windows these days, all I've got is daft high end audio apps like wavelab, and for anything like this I'd use Linux. But 2 secs on google looking for "free mp3 to wav" (and paying close attention to what you download and who from), should sort you out.