I add a My account webparts and i have an error:

Server Error in '/' Application.

The control collection cannot be modified during DataBind, Init, Load, PreRender or Unload phases.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The control collection cannot be modified during DataBind, Init, Load, PreRender or Unload phases.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

now, I'm on the tab page are bi or design error, not sure how to remove the web part just added. If no other way, not supposed to delete all the pages were created?