[niteriderxp]

Is the certificate expired?

Have you installed the certificate itself or the CA's certificate, the latter should be installed?

Is the date on your computer and/or phone correct?
A certificate will fail validation if a device's time is before issue date or after expiration date.

Is your phone in Global mode instead of CDMA mode, I have seen issues where the phone's clock gets a weird date in Global mode.

One can obtain a public CA signed UCC cert from GoDaddy for $90/yr that works out of the box. Might be a better option if you have the budget for it.