HDCP error using 23" Cinema HD Display with Mac Mini 2010. Solutions??

So I recently purchased a 2nd hand 23" Cinema HD Display to be used with my Mac Mini (2010)

However, when I view some videos that I've purchased in iTunes - I get the error of

"The selected movie won't play on your display. This movie can be played only on displays that support HDCP (High-bandwidth Digital Content Protection)."

Can anybody help me with this? Is there a way around this, as it seems unfair that my legitimate purchase can not be viewed on my Apple display?

I currently have this connected via a DVI to HDMI adapter.