line 189, php4isapi.c:

lpECB->ServerSupportFunction(lpECB, HSE_REQ_SEND_RESPONSE_HEADER_EX, &header_info, NULL, NULL);

should read:

lpECB->ServerSupportFunction(lpECB->ConnID, HSE_REQ_SEND_RESPONSE_HEADER_EX, &header_info, NULL, NULL);


see http://msdn.microsoft.com/library/sdkdoc/iisref/isre0zw8.htm

extract:

BOOL ServerSupportFunction( HCONN ConnID, DWORD HSE_REQ_SEND_RESPONSE_HEADER_EX, LPVOID lpvBuffer, LPDWORD lpdwSize, LPDWORD lpdwDataType );



the extension control block is being passed back instead of the connection id. oops.