If you're using the IBM AFP Print Driver (http://www-1.ibm.com/support/docview.wss?uid=psd1P4000384) on Windows Server 2003, your applications may fail if you upgrade to Window Server 2003 SP1. Specifically, calls to the GDI function EndPage may return 0, which has the name ERROR_SUCCESS, and the message "The operation completed successfully."
This is caused by the order of particular GDI calls. Specifically, DeviceCapabilities can't be called when the document is active (i. e., in between the calls to StartDoc and EndDoc). Calling DeviceCapabilities while the document is active is supported by the GDI library, but isn't often done in practice. The work around is to gather all the device capability information you need prior to starting the document.