http://bugs.winehq.org/show_bug.cgi?id=6971
--- Comment #227 from Jake Meigus777@aol.com 2009-02-24 20:04:01 --- I can confirm that on a 64 bit Lenny, downloading Wine 1.1.15 (you have to add the repository) and setting the dinput key to 'force' fixes the problem! At least on Unreal Tournament 2004.
Also: I tried forcing the key on version 1.0.1.1 or whatever. (the highest Lenny showed normally) Didn't work at all for Unreal Tournament 2004. I even tried disabling it, it didn't affect Deus Ex, an Unreal engine game which DID grab the mouse properly. And UT2004 didn't work normally with the updated Wine - it had to have both the update AND the force key.
Good luck, hope this helps.
P.S. to be specific, my problem was the "mouse gets stuck when it reaches the edge of screen"