Difficulty installing The 7th Guest on DOSBox
Solution 1:
I'm going to try to answer generally, since I don't have this game.
Some games expect you to have C:\
since probably 99% of Windows/DOS installations use that as their main drive. So try (for example):
mount C /home/user/oldgames
And then run the installer and try installing it under C.
If your path is something like /media/external
then it could be that the drive is too big, and the installer thinks the drive size is a negative value or something due to integer overflow. In that case you could try making a small partition and using that instead. This is assuming DOSBox uses the max available size. You can specify a size (in MB) like so:
mount C /path/to/whatever -freesize 1024