If the firewall service is disabled, you will get the following error.
Firewall service is disabled. Visit our support center to learn to enable it
How to fix this:
i) Open run (windows key + R).
ii) Type “Services.msc” without quotes and hit enter.
iii) Scroll down to find “Windows Firewall” and right click it.
iv) Start the Windows Firewall service.
Now launch the mHotspot, it should work fine.
If you can’t enable firewall for any reasons, internet sharing should be enabled manually. See this link for tutorial.