PageRequestManagerParserErrorException

I'm having this error, but I don't have trace turned on as far as I can tell. I am using this in a site with in a site. Here is my current config section where it talks about trace:
<customErrors mode="Off" defaultRedirect="GenericErrorPage.htm">
<error statusCode="403" redirect="NoAccess.htm" />
<error statusCode="404" redirect="FileNotFound.htm" />
</customErrors>