KEYBOARD: I can't type \ or : in DOSBox.
This can happen in various cases, like your host keyboard layout does not
have a matching DOS layout representation (or it was not correctly
detected), or the key mapping is wrong.
Some possible fixes:
Use / instead, or ALT-58 for : and ALT-92 for .
Change the DOS keyboard layout (see Section 8: "Keyboard Layout").
Add the commands you want to execute to the [autoexec] section
of the DOSBox configuration file.
Open the DOSBox configuration file and change the usescancodes entry.
Switch the keyboard layout of your operating system.
Note that if the host layout can not be identified, or keyboardlayout is
set to none in the DOSBox configuration file, the standard US layout is
used. In this configuration try the keys around "enter" for the key \
(backslash), and for the key : (colon) use shift and the keys between
"enter" and "L".