It's not new: https://bbs.archlinux.org/viewtopic.php?pid=1137700
Try using dosbox.

Thank you for the comment.
I've had tried it (dosbox). It's wonderful but this Clipper's db-app won't run inside it. I've posted in dosbox's forum, rebuilded dosbox-svn with custom settings but with no success.
http://vogons.zetafleet.com/viewtopic.php?t=32987

dosemu was my last hope. It's my sad story about migrating from 1,44' PC-DOS floppies with Netware ms-dos clients to linux-based solution.
I just wanted to try run my headache's app inside dosemu to see if it will work there.
But I have no success in trying to run dosemu. If I point command.com to it manually it won't see inside dirs. Something is wrong.

It wants root privileges. I'll check what should we do to run it from generic user.

Thank you very much for the effort. It would be good to fixing this issue.
But now, one good friend from dosbox's community has helped me with my app to run it in dosbox. So, this is not so important for me personally now as it had been before.
Nevertheless, it might be necessary in a future.
Whatever the case, I'm thankful.

dosemu-svn from the AUR builds and runs fine. That may be an option for you.

I get segfaults when I try to run dosemu (x86_64) as a regular user. Is this what happens to you guys?

Running FreeDOS in Qemu or VirtualBox may also be an alternative.

Says it's fixed, but I have this exact error message with 1.4.0-9

does it work after
sysctl -p /etc/sysctl.d/dosemu.conf
?

What if you run it as root?

Still doesn't work, and will respond with any questions or answers.

The final comment by Sergej does not work as root, either.

Would love for this to be fixed!

I don't know. It starts on my machine.

Could you please do clean installation? remove dosemu, check that there are no /etc/dosemu,/usr/share/dosemu, install package and reboot

I did a little further tinkering, and installed a new 64bit VM, alongside my 32bit VM (which is the one that currently doesn't work). The 64bit VM works like a charm. So maybe it has something to do with it being a 32bit OS that causes it to fail?

I completely removed dosemu from the 32bit VM, made sure there was nothing left over from removal (even from the self-compiled version I installed -- which did work), rebooted my machine, and got the same results. config.sys and autoexec.bat don't seem to be able to be read whatsoever.

Just odd that it works on a barebones 64bit Arch install, and not on a 32bit one.

Also, by now pacman installs dosemu-1.4.0-9, which is the version I'm installing here.

It actually doesn't even seem like FreeDOS is started at all, like it is in the 64bit OS.

Please test the version 1.4.0.8-1. It solves the problem on my system. I cleaned up all patches from the package, so please report if you found any regression.

Thank you for the fix, György. That seemed to do the trick on my i686 install. I also tested it on my x86_64 Arch VM and it worked there as well.

Still doesn't work, and will respond with any questions or answers.

The final comment by Sergej does not work as root, either.

Would love for this to be fixed!