The demo runns fine with TOS 1.04.
If you reset the emu and the disc didn't start, you havn't disabled booting from harddisk.

btw the hatari UI is a pain in t. a.

You can better take access via shortcuts to start the original hatari menues.( For example : the blue arrow key and o ) .

Is there a permanent possibility to calibrate the mousepointer ?
The best default calibration is under TOS 2.06.