Erro com ScriptManager

ERRO:

" The control with ID 'Municipio' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.

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.InvalidOperationException: The control with ID 'Municipio' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.

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."

eSTOU Migrando um web site do VS2005 dotnet2.0 para VS2008 dotnet3.5 . Após consertar toda a parte de ambiguidade do Scriptmanager, o projeto conseguiu rodar, porém quando entra na página que tem ID municipio aparece este erro. Olhei o Source da página que contém lá o scriptmanager. Gostaria de ajuda!