Probably something horribly wrong with you LOL.. kidding, kidding.. um
Alrighty, try logging in as root, and browse into your /home directory.
If you have KDE, this is easy. Load kde, pull up the home directory in konqueror, right click on a users folder, select properties, and, see if they own the folder, and their permissons for writing files...
If your stuck to a text terminal..
try manning chown, and see if you can handle setting permissions with it?
If ya dont wanna do all that. Try being root, and deleting your other users, and re-creating them.
**edit**
Whoohoo! Post 100! :-D