mp3 files properties

Hi there,

I have the following problem: when I access the
properties of an mp3 file, some allow you to enter a good
chunk of information, while others only allow you just
track number and title and that's it.

In general the latter files, give me a "Error occured
during a write operation" error message and I cannot edit
them. Anyone has a clue on what to do? or why seemingly
similar files are different?
Thanks,

Alex