Help No webbrowser connectivity while on a data connection

[Ludoc]

I just got the HTC Sliver Desire. It's a great device. I have noticed (to my delight) that while connected to my home wireless network, everything works just fine (surfing, mail, etc..). But when I'm connected to a data network on the road (local Belgium Provider Mobistar) the pages in my browser do not load. All the other app's work (including mail, twitter etc..) but i cannot surf. The connection is there, but something is preventing me from web browsing. I have got android 2.2 with browser version Webkit 3.1. Thx!