Hello Paul,
The only known issues that can cause this are:
1. Incompatibility with the BullGuard version: it has to be the latest one available BullGuard 8.5 or 8.7 and on 32 or 64 bit (depending on what system you have, you should use BullGuard for Windows 7 and BullGuard 64 bit for Windows 7 64 bit). You can find the Windows version by typing "winver" in the Start menu.
2. Language settings might trigger the same error, so you should be set on English.
3. If you are trying to install from a CD, the kit might be the issue so you can try to install from our website as you can see
HERE.
If you still have issues after checking these steps, then please contact us via email to support@bullguard.com or Live Support Chat
HERE.