Using GWT getting 405 error message on IIS 7.5

I have inherited a project that is using GWT to post login information via a form. According to Firebug, its coming back with a 405 error.

I have tried the directions on: IIS 7.5, Web Service and HTTP 405 error

That didn't fix the problem. I turned on Failed Request tracking and this is the error that I see:

MODULE_SET_RESPONSE_ERROR_STATUS Warning

ModuleName="StaticFileModule", Notification="EXECUTE_REQUEST_HANDLER", HttpStatus="405", HttpReason="Method Not Allowed", HttpSubStatus="0", ErrorCode="Incorrect function. (0x80070001)", ConfigExceptionInfo=""

Thanks!