Summary: When I submit a form (via POST) to php more than 120 seconds after the form was first called I get a 500 server error. If I submit before 120 seconds, the form works fine. I'm obviously encountering some kind of timeout but I don't know where to look. I've enabled failed request tracing and received the following error: ModuleName="FastCgiModule", Notification="EXECUTE_REQUEST_HANDLER", HttpStatus="500", HttpReason="Internal Server Error", HttpSubStatus="0", ErrorCode="The I/O operation has been aborted because of either a thread exit or an application request. (0x800703e3)", ConfigExceptionInfo="" I don't understand why it matters when the form is submitted relative to the time the form is first rendered (note: the actual form processing takes a fraction of a second). Shouldn't these two requests be stateless? Suggestions? Configuration: Windows Vista SP1 IIS7 php 5.2.x under fastCGI This is a development server running on my laptop. All calls to IIS are coming from localhost.