Can't access Google on Myriad browser

[rnredner]

I recently bought an LG Convoy 3 phone that is equipped with a Myriad mobile web browser (version 6.2.3.2).  Whenever I try to access my Gmail, or even the Google homepage, a yellow box pops up with the following message: "Security Error: Untrusted server certificate." 

I was able to look at the root certificates this browser likes (VeriSign Inc, GTE Corporation, Entrust.net, Thawte Consulting cc, and yet again VeriSign Inc), and the one I think Google uses (GeoTrust Global CA) isn't there. 

This is a really big problem for me.  I bought this phone specifically so I could use it to access my Gmail and Google calendar when I'm away from the computer.  What can you do to fix this?