JE,
You didn't say which version of Paradox 4.5 you're using, the DOS version or the Windows version. If you're using the DOS version and you're using it under a reasonably recent version of Windows (e.g. Windows 95 OSR2 or later), you should be able to start any program using
Code:
execute( "start theprogram.exe" )
However, keep in mind that neither version of Paradox 4.5 supports long filenames. So, if you're trying to start something called "My Long Program.exe," you'll need to determine the short filename (8.3) and execute that instead, e.g. mylongfi~1.exe.
Finally, if you're still having problems getting it to start, you might try creating a batch file and starting it that way.
If this doesn't help, we could use some more specific details about the program you're starting, the version of Windows you're using, the specific version of Paradox you're using, and the content of any error messages.
Hope this helps...
-- Lance