John, you are right. I made a mistake, i typed pbwin instead of pbmain in my pseudocode. pbwin is a keyword that is used to select the PowerBASIC compiler in the #COMPILER metastatement, not the function name of the entry point. Sorry about that.
That said, i think i recall, that no special configurations are required for the Oxygen compiler when PluriBASIC is installed (when no special paths are used during installation), it automatically should look for it where the installer puts it, but a wrong configuration can lead to dependancy errors.
May i know where did you install if and what path you used for the Oxygen DLL?