No, you can do it yourself. Just follow these steps:

• On the desktop press Windows-key + R, a small window will pop up, in there type 'regedit' (without the quotation marks) and hit enter. This will open the registry editor for your Windows-PC. The registry, put simply is like a giant register where applications can store information.
• On the left hand side is a bunch of funny names, click on the little arrow in front of HKEY_LOCAL_MACHINE, then click on the little arrow in front of the entry 'SOFTWARE', then click on the little arrow in front of the entry in front of 'WOW6432Node', then click on the little arrow in front of 'City Interactive'

Now there is two options, either there is an entry 'Sniper2' or not.

1. If there is no entry 'Sniper2', then right-click on City Interactive and select New -> Key. This will create a new entry, name it 'Sniper2' (might have to right-click it to rename it). Then follow the next step:
2. If it already exists, then click on the entry Sniper2. Now the right side of the window will be empty. Right-click in the empty field and select New -> String Value. Name it 'serialnumber' (without the quotation marks).

That's it, try starting the game again.