So I did some additional testing and wasn't able to make it work either, even on an SVN build, despite finding some clear advice to indicate my previous config suggestion was correct. That said, that particular page doesn't give very good advice on the Linux side; on any Debian-based machine you should just add yourself to the dialout group and not need to change permissions on the device file. If you got it working in Linux already you have likely done this.
I was, however, able to get it working fine in QEMU if that's an alternative for you. VirtualBox should do it too, though I believe QEMU has better DOS sound device emulation. Both of these would require bootable DOS or FreeDOS installation media of course. Let me know if you want any advice pursing this approach.
Sorry I wasn't more help.