[The Fifth Horseman]

I was pretty close with the generic install instruction, here's precise ones:

Type in install.
When prompted to select the drive to install the game to, you should have C: available as the only option. Click OK.
The installation path should be set to C:\DW2 . If it's not, set it to that. Press Enter to confirm.
Click OK after the installation completes.
Highlight "Select and configure digital audio driver" and press Enter.
The first highlighted option should be "Creative Labs Sound Blaster 16 or AWE32". Else highlight that one. That's the one you want, so press Enter.
On the next screen, highlight "Skip auto-detection and configure sound driver manually" and press Enter.
I/O Address should be given as 220 . If not, set it to that. Highlight "Continue" (down arrow) and press Enter.
Highlight Done and press Enter.

Alt+TAB to Windows and replace DWB.exe with the patched version as described before.

Alt+TAB back to DOSBox and you can start the game by typing DW2. ALT+Enter switches between fullscreen and windowed modes.

Are you experiencing the color issue after switching to fullscreen with this copy of the game and this copy of DOSBox?