What's wrong with my 6600?

[habble]

It never gives me a message alert tone on any profile! There's no sound, or even popping up of the message x message(s) received but the envelope icon just appears.

This is very strange. I don't know if even calls doesn't get through.

There is a midi file set in the message alert tone and ringing is on the call alert.

Should I reformat the phone? I don't know what wrong but I only have 3 apps - Ringtone Studio, Fexplorer and Smart VCard.

Another thing is sometimes when doing certain operations like transferring messages to My Folders, this message appears: 'Cannot complete write to disk' - anyone knows what this means?

Thanks in advance.