Error on gallery when logged on as admin

Hello,

I have my gallery working again after a crash of my server. But now I get the following error on the top of the configpage:

Notice: Trying to get property of non-object in D:\Inetpub\gallery.autohobbyclub-oirschot.nl\setup\init.php on line 31

Warning: Cannot modify header information - headers already sent by (output started at D:\Inetpub\gallery.autohobbyclub-oirschot.nl\setup\init.php:31) in D:\Inetpub\gallery.autohobbyclub-oirschot.nl\lib\lang.php on line 342

The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful):http://gallery.autohobbyclub-oirschot.nl
Gallery version: 1.4.4-pl6
Apache version:
PHP version (don't just say PHP 4, please): PHP Version 5.0.5
Graphics Toolkit:
Operating system:Server 2003 (Windows NT SERVER 5.2 build 3790)
Web browser/version (if applicable):