Jr2swiss,
When are you getting the message? Is it when you are uploading the game folder to the Gamepark using GP32 Manager by any chance?
If it is then use the modded version of GP32 Manager 13.2(?) that allows filenames other than 8.3 to be uploaded.
If it isn't then please state when you get this message.
And Joecool I also think that the game is awfully slow with poor framerates. Fenix games seem to look good but play poorly to me.