I have the same problem and have followed every suggestion posted but the problem still persist. Is there any other way I could get around this.
I can't even open the zimbraAdmin page, as I get a blank page when I get there.
I haven't changed anything, and my last upgrade was about three months ago and everything was working fine until today.
I'm running the 4.5.3_GA OOS release under CentOs
Please help!