sorry.. just saw now that i posted into the wrong forum.. an answer would still be appreciated 😉

ummmm... you can't. You can increse overall memory, but i think you've already reached the top (64 mbs). Memory emulation works sort of like this (anybody cares to make a better explanation than this?):
* If you have both xms and ems enabled: half and half each.
* If you only have xms or ems enabled: evrything goes to the one that is enabled -> this seems to be your case.

I don't have the game, so i'm not sure what you can do... Try disabling xms too and see what happens. It can also be that the game is confused at the total amount of base memory free, and it's displaying an erroneous error message. You can use loadfix to try to correct that...
Finally, it can also be a cpu core thing. Try the different cpu cores first than anything else 😉
Hope that helps

Don't mix up expanded memory and XMS.
Expanded memory normally refers to EMS, but might be also used for extended memory.
While EMS and XMS were techniques to manage a computer's extra memory, extended memory wasn't managed at all, it was the applications task to manage it.
So you should try your app with XMS and EMS disabled.

well dosbox does like the later emm386 and qemm manager a sort of sharing.

Anyway try 0.61 as i lowered in 0.62 the amount of memory you can have to 63 mb

but a game wanting that much memory will probably not run very fast.

i suppose you should try
memsize=16
in dosbox.conf