No page refresh after submitting in administer menu

Hello,

When I edit something in administer menu (fx Site configuration > Date and time), my change doesn't show when I hit the submit button. It jumps back to the state it had before my change, but if I manually click or reload the page then the change appear. Example: if I change the value in "First day of week" from Sunday to Monday, then the page shows Sunday again after submit, but after reload then the page shows Monday. I don't have that problem, when editing a published node.

Any suggestions about why this happens?

I'm running a multisite on Drupal 5.6 on an Apache server with php 5.2.3 and mysql 5.0.41 hosted at www.servage.net

Kind regards
Torben Heikel Vinther
www.raabjerghytten.dk