Firefox 3 conflicts

We have just upgraded to Firefox 3 on a Windows XP mchine and immediately had two problems with other programs. iTunes library would not save and became damaged resulting in irreparable loss of library settings, folders etc. WordPerfect 12 could not save a document reporting Disc Full (not the case). iTunes support reports the problem we had is usually caused by another program's security interfering with file save. It's possible it is coincidence but I have to suspect these problems stem from Firefox 3. Can you advise? Thank you.
-Ron S