"Have I corrupted my package manager?"
You have probably corrupted your rpm data base.
"Is there another way to get into the package manager from the command prompt possibly?"
Yes. Log in as root and use the CLI rpm command. See:
to rebuild the rpm data base.
rpm -qa | sort > /root/all.rpms.txt
to create a file with every rpm name in it. If this command works then check the list for reasonableness.
Be prepared. Create a LifeBoat CD.