IMPORTANT : Close MT4 with the system chart or template OPEN
Do Not close the chart first and then MT4, you risk that the License key will be stuck in the Windows registration file and you wont be able to re-open the system templates.
Should it happen, do the following.
Open your MT4, apply the provided template > Close MT4 > Restart your computer > Reopen your MT4 and apply the provided template.
If your system is used on multiple MT4 installations, follow the same procedure, open the MT4 where the system was working the last time and follow the above sequence.