Help! ibookG4 problem. won't save stuff...

This week my ibook G4 which has been great since I've had it is finally starting to act up on me.

I am unable to save documents. Also, I've noticed when I'm sending e-mails I can't attach files.

I have a suspicion that it may be something with the hard drive but I have no idea.

How do I repair permissions?

I'm running the default OS...which I think is Tiger?

System Software Overview:

System Version: Mac OS X 10.4.11 (8S165)
Kernel Version: Darwin 8.11.0
Boot Volume: Macintosh HD

I haven't installed anything lately. Just downloaded a few things from itunes.

I repaired permissions and still no saving.

hmm...