Jaffer,
There are already three active systems for your license. We allow only upto 3 activations for a personal license.
We have deactivated one of the active systems and upped your activation limit. You should now be able to activate successfully.
Regarding removing deactive systems from the list, they are maintained as part of our records and do not count towards your activation limit.
So not to worry.
If you are still seeing any problems with activation, please let us know.
–Swapna
Genuitec Support