Wireless Keyboard connection problems

I bought a Wireless Keyboard just around a month ago and it worked fine. Shortly after buying it I went away for two weeks leaving it at home. When I got home I suddenly couldn't connect it to my MacBook anymore. I tried taking the batteries in and out, restarting the keyboard, restarted the MacBook, changed batteries, I basically tried every trick I knew. But it still doesn't work. I can get to the menu where I have to type in those numbers on my keyboard but there it stops. I get a message (in norwegian) saying something like this:

"Connection failed. Control that the keyboard is within the computers range, turned on and in Searchable-modus. When you are ready, click Continue and try again."

I have checked all the above, but it doesn't want to connect... Anyone out there who could help me?