Sys.InvalidOperationException when trying to edit page in sharepoint 2010

I added a webpart through VS2010. It is a Simple webpart containing ajax script manager,timer and update panel. what it does is it shows the current server time in a label. After i deploy it into my sharepoint site i get following error when clicking on edit page.

"Sys.Invalid Operation exception: Could not find updatePanel with ID 'ctl00_m_....pnlTimer'. If it is being updated dynamically then it must be inside another Update Panel."

This error goes when i remove the updatepanel in my code.How can i get rid of this error?