Cannot connect anymore
 

I have recently installed the Extra's "callender/todo etc" and now I can no longer connect to my wifi. actually thats nlt quite true, The connection manager says it's connected andshows a signal level off all for bars, after about ten minutes it displays "sent = 2.44KB" and "received = 5.56KB"
But when I tap the web and try to go to any web site it displays a box saying "Network Problem"
In the bottom left of the screen it says "connecting and the icon to the left continually rotates. If I tap OK in the Network Problem box the connecting dissapears and nothing further happens.
Any suggestion anybody