Looks like your system is beginning to show its age.
First thing: Backup your password database to another machine/thumb drive/network disk. In a pinch, send it to yourself via e-mail (assuming you have a non-trivial master password).
The default database is pwsafe.psafe3, and by default it's in My Documents\My Safes.
If you can access another machine, you might want to install PasswordSafe and check the integrity of your database. If that's ok, then looks like its time to reformat your old machine's disk, or at least run some serious diagnostics on it.