Firefox displays page in a wrong way

[Ivan]

Binary package hint: firefox-3.5

I've fount this problem when I've tried to use OpenX (www.openx.org). I've installed this system on my site but I can't use it in firefox, because it displays it in very bad way. Any other pages I've ever seen looks fine in FF.
Opera and IE works fine here. I've seen this bug in OS: Windows XP, Windows Vista, Ubuntu Linux; in browsers: FF 3.0-3.5.
Just see screenshots, all pages of OpenX are displayed badly in FF.
How to fix it? Any ideas?

ProblemType: Bug
Architecture: amd64
Date: Thu Nov 12 19:30:51 2009
DistroRelease: Ubuntu 9.10
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
NonfreeKernelModules: nvidia
Package: firefox-3.5 3.5.4+nobinonly-0ubuntu0.9.10.1
ProcEnviron:
 LANG=ru_RU.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-14.48-generic
SourcePackage: firefox-3.5
Uname: Linux 2.6.31-14-generic x86_64