I had a problem when trying to su. Everytime I tried to su it gave the following error:
su: Bad item passed to pam_*_item()
Since I didn't find my solution on the internet (the only solution I could find was removing wrong entries from /etc/environment), I'll post mine here:
I had a floating equals-sign in
You should check that file, it should only contain something like
If that doesn't fix your problem, you might want to check your /etc/pam.d/su for strange entries.