Specify parameters using the parameterList method or INI file method. Refer to the documentation. This mis most likely to occur under Windows 3.1, and less likely to occur under Windows 95 which manages virtual memory somewhat better. If there is not enough memory to launch another application simultaneously, you should use zLaunch instead. In either case, make sure you specify an appropriate minimum configuration and tell users to quit other running applications.
Some applications only look for documents in the working directory.
Even though the file path listed in the error message may appear correct, the application requires that you set the working directory to the folder containing the document. This may be a folder other than the one containing the application or the Projector. The working directory is specified as a parameter to several of zOpen's methods, including zOpenDoc, zPrintDoc, zOpenExe and zOpenCover. Windows 3.1 can be installed to run under Windows NT to handle 16-bit applications. The easiest solution is to use a 32-bit projector under Windows NT, which will not require WOW in the first place.