My computer specs are:
Windows 7 64bit
Intel i5 2.90Ghz
4GB Ram
Nvidia GTX 550
Videocard drivers and directx drivers are up to date, checked today.

And when trying to start the game a window pops up with
"0a9e372d3b4ad19135b953a78882e789" error messages and what not.
Never encounted this before and I have over 150 pc games new and old,
some of which didn't work aswell but I managed to fix. This game however
I can't no matter what i try.

Solved it by installing special drivers for Battlefield Hardline. Who would have thought....

I solved the black screen problem.
The problem was my firewall software, Private Firewall. Private Firewall has a process monitor, so when a new process starts it stops it and asks the user for permission to allow the EXE file to continue. When Oceanhorn - Monster of Uncharted Seas starts when launched it shows a black screen when loading, Private Firewall's process monitor stops Oceanhorn.EXE while the loading screen is showing. The black loading screen covers Private Firewall's window when it asks for permission for the process to be allowed, so I couldn't see it. You cannot select the Private Firewall window or even start Window's task manager. Therefore it seems that the program has crashed and just stuck on the black screen.
I solved the problem by manually adding the Oceanhorn.EXE file to Private Firewall's "allow" process list. After I did that the game started normally.
Maybe many people who have the same problem just need to check their computer software's process monitor or security software.