Vicklaw: After you save the war3map.j in JassCraft, open the .w3x in MPQMaster, right click on the war3map.j in MPQMaster, choose Delete, confirm Yes if a message pops up, right click in the window, choose Add File..., find the war3map.j you saved, and choose to add it. Then, go to the top, choose Tools, and then Compact(Flush). Then you're done.
Crucial: You probably forgot to delete the (attributes) file. Open the map in MPQMaster, find the file named (attributes) ; it will be right below any folder in the map, at the top; right click on it, and choose Delete. If a message pops up asking if you're sure, choose Yes. It should work after that. If not, open the war3map.j in JassCraft, and press F9 to run the syntax checker, to see if you messed up there, and if so, where. If you there's no errors, and the attributes file is deleted, yet it still doesn't work, request it.
Micro: See my post on your topic:
post64944.html#p64944