MicroCode Studio Plus won't use mpasmwin

In the MicroCode Studio Plus (mcsp) helpfile it tells me this:

"By default, MicroCode Studio will use the windows based assembler, mpasmwin.exe. This is preferred over the command line version (mpasm.exe) because it implements a better memory model."

But it does NOT in my case.
I tell mcsp where to find mpasmwin.exe but it still start search for mpasm.exe.
If I rename mpasmwin to mpasm it works.

On my older computer I use exactly the same software versions and mcsp is using mpasmwin. I can see in the mcsp window at bottom left corner: "Assembling - MPASMWIN"

I have added pbp and mpasmwin folders in System Path.
I compared all files in folders PBP, MCSP and MPASM Suite between the computers. Same.
I also tried different versions of MPASM.

When I compile using mpasm I get error:
"usbdesc.asm 5 : Cannot open file (Include File "DESCUsbProject.ASM" not found.

But If I rename mpasmwin to mpasm then I get no errors.
At the bottom left corner of mcsp it still shows "Assembling - MPASM".

I use mcsp v2.2.1.1 and pbp v2.46.

Thanks in advance
Stefan