You are from Belgium, right. I did a research here
http://oami.europa.eu/CTMOnline/Requ...n_Result_NoReg
(just type in blockbuster into the trademark name field)
and got 9 results. The one most dangerous for you is trademark #002045391 which was filed in 2001 and - thatīs interesting - was registered in 2004.
Your problem is that the trademark is also registered in Nice class 41 for "providing digital images from the internet". So your domain name could be hurting the trademark.
To be sure, contact a trademark lawyer in belgium. But most likely, you will lose that fight. And be careful asking them for money to transfer the domain. That could cause some bigger problems for you because European trademark law punishes this if you registered the domain illegally, for example just to profit from the trademark owners reputation.
Iīm not familiar with the law in Belgium, but itīs pretty much the same in all European countries which belong to the EU.