I got a sim memory full message too. Depends how many contacts you have, but this phone (plus sim) seem to be geared towards keeping all your contacts on the phone. Set it to use the phone memory and the sim card memory, it's in the settings option in Menu->Contacts. Mine was set to have the default memory be the sim card, which it didn't like.

I couldn't quite get the hang of the plectrum thing...I prefer the stylus thing. Except that it took me ages to work out how to pull it out, it's really stiff on mine!