[zirkoni]

You should do this to install the game:

mount c c:\progra~1\dosbox\games
imgmount d c:\progra~1\dosbox\games\fshock\terminator.img -t cdrom
d:
install.exe

In DOSBox now install the game to C:\fshock (which is c:\progra~1\dosbox\games\fshock in Windows)

And to start the game:

mount c c:\progra~1\dosbox\games
imgmount d c:\progra~1\dosbox\games\fshock\terminator.img -t cdrom
c:
cd fshock
shock.exe

You really shouldn't install the game in C:\Program Files (x86)\ , C:\Program Files or C:\Windows because those directories (and everything in them) are write protected by default (meaning that DOSBox can't create or edit the files unless you run DOSBox as administrator).

Also, don't use file/folder names longer that 8 characters inside DOSBox (you can use long file names in the mount commands, just wrap the paths inside quotation marks "").