Atomicorp

After a reinstall of psa-horde (via YUM)
I'm working with CentOS 4.3
I managed to get the mail working,

but for some reason, if you click a folder, the sidebar "disappears"

After the upgrade via yum of php4 to php 5.0.4,

I noticed horde was working, but, all mail-related stuff doesnt work,
I only get empty pages when I try to go to an inbox.

Any Ideas what needs to be changed/installed/upgraded?

What information do you need about my server?