X session error

[Mrbizz4]

I am having problems logging into my gnome desktop environment as my regular users.  I can however log into it as root.  When I attempt to log in as a regular user I get a message which states the following,"Xsession warning: unalbe to write to /tmp;xsession may exit with an error."  When I look at the xsession-error file it states that there is not space left on device, however I just bought the hard drive that Linux is operating and I know I should have plenty of room.  It also gives me the message "mkdtemp private socket dir".    Any help with this would be greatly appreciated. Thanks Mike