The Dink Network

Hi. While adventuring around Port City, I found a castle, north from the town and agreed to help the green guy with his wife. Opening the doors there is a hell of a problem. Any ideas how to open them?

what kind of problem,fellow peasant?

You have to find the keys in the castle. Break stuff, that key has to be somewhere.

I actually found 1 C-key but using it on those doors doesen't open them. I also found a passage near the exit that was supposed to be open but still I can't make it work. Those doors resist bashing, blowing up and stuff. Any clues?
Btw. thanks for replying. Some people here are willing to help noobs after all.

Equip the key first before opening the doors.

Thanks WC. That kinda worked.