The following error indicates the certificate in question, which was in the chain of trust for the package to be installed, was revoked by the issuer of the certificate.
pkg install: This certificate was revoked: /C=US/ST=California/L=Menlo Park/O=pkg5/CN=cs1_ch1_ta4/emailAddress=cs1_ch1_ta4 for this reason: None The package involved is: pkg://test/example_pkg@1.0,5.11-0:20110919T205539Z