Shibboleth Developers

Hi All - 

I am trying to implement Single Sign on and all the certificates are valid on 
the target server, but for some reason Shibboleth is giving me error saying 
that certificate is expired. I am not sure which certificate is expired. Anyt 
help is hugely appreciated.

URL to test cert:
https://careertracker.kenexa.com

Target Server: Windows 2000, IIS 5.0, Verisign SSL

certificate that is giving error:
/C=US/O=VeriSign, Inc./OU=Class 3 Public Primary Certification Authority

Error:
ERROR Shibboleth.ShibBinding [1] session_is_valid preFetch populate 
getNewResponse send: caught SAML exception during SAML attribute query: 
SAMLSOAPBinding::send() failed while contacting SAML responder: SSL read: 
error:14094415:SSL routines:SSL3_READ_BYTES:sslv3 alert certificate expired, 
errno 0