Thanks LSS, you are running another newer version that relied on new symbols, I added those it might work now. I addresses some keyboard mapping issues between OS personalities and other fixes. Also fixed executing across personalities in the different versions.

@superfure Excellent I will test more tonight.

As a hat tip to the excellent work on rust-dos by dividebysandwitch I added rat commander as the linux personality tui.

Some tests with the recent release.

Windows versions of NDN and DN/2 now works.
DN/2 OS/2 version still doesn't work.

1synth_fork_exec entry: ds=0625 dx=87DC es=0625 bx=86C6
2synth_fork_exec: filename="DN.EXE" tail.len=0 tail_first8=[]
3handle_fork_exec: "C:\\DN2O214\\DN.EXE" size=1053524 format=lx free_pages=26528
4  fork done, loading protected-mode image...
5OS/2: unresolved NLS ordinal 7
6OS/2: cannot fix up module DN.EXE
7Bad command or file name: 'DN.EXE'

Not sure if this matters for NDN OS/2 version but I noticed these OS/2 log messages in the klog when launching it.
NDN OS/2 itself works, however.

1synth_fork_exec entry: ds=0625 dx=87DA es=0625 bx=86C4
2synth_fork_exec: filename="NDN.EXE" tail.len=0 tail_first8=[]
3handle_fork_exec: "C:\\NDN-O32\\NDN.EXE" size=1459451 format=lx free_pages=26414
4  fork done, loading protected-mode image...
5  child tid=2, parent tid=1 continues without blocking
6WARNING: sound underrun #4 written_frames=4844813 consumed_frames=4845740
7OS/2: unresolved PMWIN ordinal 701
8OS/2: unresolved PMSHAPI ordinal 115
9OS/2: unresolved PMSHAPI ordinal 114
10
11Necromancer's Dos Navigator v3.00.0012v/OS/2. 
12Based on Dos Navigator by Ritlabs...
13[DEFINES/CPU86/CPU87/OS2/VIRTUALPASCAL]
14* OS/2 (v20.45 rev. 0) detected...
15* Process ID = 3 ...
16* PCRE Version 8.45 2021-06-15
17
18OS/2: unsupported Base(272) args=0x3,0x4,0x4,0x3

On the other hand, sound underrun messages still spams the log a bit (as seen in the NDN log), even though sound is working without apparent issues.
I wonder if there are options to mitigate it somehow.

Besides, it seems I cannot launch any other OS ports of NDN from the DPMI32 version of NDN, complaining about "This program must be run under xxx" (xxx being Win32 or OS/2 depending on the port type). Perhaps this is a limitation.

And by the way... I wonder if it's somehow possible to make Windows or OS/2 processes run fullscreen, as "Make window/Make fullscreen" doesn't seem to have any effect on Windows or OS/2 processes (such as NDN ports) at the moment.