I recently tried 2.6.18.1 kernel and wine stoped working. Then I downgraded to 2.6.16.18 and wine working fine now.
I'm using a custom built 2.6.18.1 on Debian Unstable/AMD64 now, and Wine works fine for me, so this is unlikely to be a Wine problem.
I compiled 2.6.18.1 with same .config. As expected, Wine stoped working. I don't know yet why exactly this happens but fact is that with same configuration under 2.6.18.1 kernel Wine doesn't work. As you said you have 2.6.18.1 and working Wine. So please tell your compiler, X server versions and compilation options for Wine. Also I very appreciate if you send me your .config file so I can try it on my system (I use Debian testing amd64 distribution).
I have errors like these ones when I try to launch something with Wine:
fixme:seh:check_no_exec No-exec fault triggered at 0x401000, enabling work-around fixme:seh:check_no_exec No-exec fault triggered at 0x4c8ad4, enabling work-around err:seh:setup_exception stack overflow 40 bytes in thread 0009 eip f7c9e9ff esp 00230fd8 stack 0x231000-0x340000
Some applications even open window but soon after these messages crash. Factually, all my Windows apps crash! Only exceptions that I found are winecfg and notepad, but everything else including all my games, viewers, players and editors crash. Under 2.6.16.18 Wine works perfectly.
P.S. I use gcc 4.0.2 and Wine compiled by following commands: LDFLAGS="-L/lib32 -L/usr/lib32 -Wl,-rpath,/lib32 -Wl,-rpath,/usr/lib32" ./configure \ --x-libraries=/emul/ia32-linux/usr/X11R6/lib/ --x-includes=/emul/ia32-linux/usr/X11R6/include --with-x && \ make depend && \ make all && \ sudo make install;