Downloading Certificates

when i download a certificate and attempt to login on the secure server i get msg page cannot be displayed. i’m using w2k and IE6. in the event viewer under systems i get an error in schannel event ID# 36870. fatal errored when attempting to access the SSL client credential privite key. The error conde returned from the crytographic module is 0xffffffff. where in the registry is the problem? i can get the certificate by email and import it and it works.