Blank Pages with Theme tab in user pages and admin pages inside joomla

Hi all,

I am using Joomla + G2 and I have the following issue: If I click on the theme tab (user page), I have a blank page, if I go in the admin section, the same goes with theme tab and a few other links. What is the solution, is it maybe a URL issue or something like that?

many thanks for helping ,me.

Michel

Gallery version = 2.2.4 core 1.2.0.6
PHP version = 4.3.9 apache2handler
Webserver = Apache/2.0.52 (CentOS)
Database = mysqlt 4.1.20, lock.system=flock
Toolkits = Exif, Ffmpeg, LinkItemToolkit, NetPBM, Thumbnail, Gd, ImageMagick
Acceleration = none, none
Operating system = Linux vps151.whitevps.com 2.6.9-023stab044.4-smp #1 SMP Thu May 24 17:20:37 MSD 2007 i686
Default theme = floatrix
gettext = enabled
Locale = en_US
Browser = Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en) AppleWebKit/523.12.2 (KHTML, like Gecko) Version/3.0.4 Safari/523.12.2