Forget the last post. I figured it out right after I posted the question and the board won't let me delete the question. All is working right.

mathmap is preinstalled in my gimp portable so sure does work on the portable, no problem

maybe you forgot that MM has not only a exe file but also several dll and a folder that should be placed in the gimp user folder
(or what in your portable correspond to the user folder... )

no idea what portable version you have, if you can't find the correspondent of the user folder you may try to place the MM folder in "share"

Yes i also have MathMap installed in portable and it works fine for me.
My advice is to download and install MathMap again.That way you make sure to get all the correct dll files you need.

Can you share how you got it working GMS? A list of what files need to go where would be great.

It should be simple :
everything should be in a plugin folder (i suggest a dedicated one to keep dll and exe in the same place, but is not strictly needed, except to avoid problems as that from GSM )

everything BUT the Mathmap folder (that with inside the filters code and another few files) that should go in the gimp user directory