Client Certificate Management Problem

I have Windows XP SP3 machine that I cannot get the 3rd party cert installed on. I can do everything else I need to the machine, but I cannot install the cert. This cert is working fine on hundreds of other machines. When I run the Client Certificate Management tool I receive the following results from the task:

Client Certificate Management
Object: CN=WSUS Publishers Self-signed
Status: Failed

Details: NotFound Not found

Has anyone else seen this issue before?

Thanks.