Well, it could be that it needs ultramid to be either loaded or unloaded, if you autoload it...then don't, and if you don't, start ultramid before starting the game and its setup.
Mixing cards is possible, easier than with real hardware, too.

I do wonder who wrote "Cannot initalising card" as an error...

I do wonder who wrote "Cannot initalising card" as an error...

That's easily explainable:
Since probably the other window says "Initialising card" so they were prolly copying the code and replacing the text and they forgot to adjust the middle part and they were anyway busy making an excellent game.

The game uses HMI sound drivers, and the setup built into the main executable is rather limited in the available hardware settings for GUS. DOSBox's default GUS settings are not automatically detected and some are not available for manual selection, which may be related to an issue discussed in this thread: The Terminator: Future Shock/SkyNET - Ultrasound doesn't work for music

Unfortunately, there is no SETUP.INI to modify in this case; possibly because the game has its own setup rather than using an HMI setup program. With no other obvious options, I manually edited HMISET.CFG to use DOSBox's default GUS settings:

1[DIGITAL]
2DeviceID    =  0xe023
3DeviceName  =  Gravis UltraSound
4DevicePort  =  0x240
5DeviceDMA   =  3
6DeviceIRQ   =  5
7
8[MIDI]
9DeviceID    =  0xa00a
10DeviceName  =  Gravis UltraSound
11DevicePort  =  0x240

With this configuration the digital sound is fine, not broken up like it is with autodetection; and the MIDI music sounds fine too. I used official DOSBox 0.74 with default settings except gus=true. Note that you must have the GUS instrument patches installed in C:\ULTRASND (or where the ULTRADIR environment variable indicates) in order for the music to work.

Thanks, it plays flawlessly!