Hi Anja - Any solutions that could be used would be more complicated than simply tweaking a small MediaLab value. One way to approach the situation may be to remap the spacebar to the enter key. The following link explains how to do this:
http://vlaurie.com/computers2/Articl...p-keyboard.htm

You may also want to look into the following link, where I explain how a user can disable a key on their keyboard:
http://www.empirisoft.com/support/showthread.php?t=3233

Let me know if this helps. Although the solution isn't quite ideal, it should work.