That’s really odd. Like with all oddball issues, try switching themes and disabling plugins until you find the culprit. What server are you running?
Also enable debug mode and look for errors.
What URL does the browser attempt to navigate to when you click on Widgets?
Thanks for your suggestions. The URL is: http://www.mym.nl/wp-admin/widgets.php Which seems OK to me. The thing is, I allways had the 10-20 theme (never cheanges, apart from updates), so I would think that it’s not the theme. I will start disabling plugins for a start.
OK, that helped: the plugin that messed up was: Google Analyticator! THX!