Then you can self-apply that patch of course and live with the possible side effects.

Hey, don't know if you've solved your "Floppy Disk Swap" problem, I don't think DosBox does this unless you have .img and use Boot to swap by pressing alt+F4 (as someone else mentioned.) If you don't have images, simply do this:
0. Make backup of your game (always)
1. Run DosBox
2. Mount a destination drive for your game c:\
3. Mount floppy disk #1 to d:\
4. Run "d:\install.exe" or equivalent
5. When asked to swap floppies, go to your system's finder/explorer and navigate to the "floppy disk 1" folder
6. Copy the contents of "floppy disk 2 " folder into your existing "floppy disk 1" folder (make sure to overwrite any files with duplicate names)
7. Go back to DosBox and tell it "OK, I've swapped the floppy" and installation should continue as normal.

Here's another site that gave a less specific way to do this, with an old classic game DoTT: http://www.dosbox.com/wiki/GAMES:Day_of_the_Tentacle

Hope this helps, cheers