PageRequestManagerParseErrorException

Hello. I'm have the problem with UpdatePanel. When the user does click on de button I call a method

Button1_Click

This method call other page in modo modal where the user type a password. If this password is ok I'll try to use

UpdatePanell2.Update() but I can′t call the page2 in modo modal because appear this error.

Read this to avoid this issue:

http://weblogs.asp.net/leftslipper/archive/2007/02/26/sys-webforms-pagerequestmanagerparsererrorexception-what-it-is-and-how-to-avoid-it.aspx