Thought I'd give Pac-Man Collection a whirl on BlueMSX, but I can't get these instructions to work:
To run the game in blueMSX, first select File > Cartridge Slot 1 > Insert. In the Insert ROM dialog box, highlight the Pac-Man Collection rom file and then in the file ROM Type drop-down at the bottom of the dialog box, select ColecoVision MegaCart®. Then click on the Open button. (Ikrananka).
Did you get Pac-Man working on the Blue MSX J?