Getting an error when trying to import a certificate into the "Trusted Root Authorities"

I am having trouble importing a web certificate to the "Trusted Root Authorities" store. We keep getting the following message:

"the import failed because the store was read-only, the store was full, or the store did not open correctly"

The user is a local Admin and we were able to import it into the "Trusted Publishers" Store where it also has to be added.

I tried deleting a few certificates from the store and we are still getting the error.

She is running XP.

Any Ideas?

Thank you,

Evan