JJM can be compatible to wine but you have to make a lot of steps,
at first install winetricks, then dotnetfx2 (net framework 2), directX9 ( both with winetricks) and adobe flash player (a sure working version is at: jj2.ath.cx/fs.exe) on wine too (Flash will fix the ole error on the beginning and make it possible to play music and video).
You have to enable the usage of a soundcard too (winecfg).
I tested jjm with wine 1.2.1, about it's stability of JJM and jj2 i cant say mutch, but older versions as 0.97 of wine wont work with the current JJM...

In next version will be a linux mode but at the moment it's fixing only a small bug in the chat system of jjm that come thx to wine (windows user should not use this), JJ2 often crashed at the serverlist, when i used JJM, i'll try to make it 100% compatible to wine (i use ubuntu the most time since a month) but this will take more time...

The best solution at the moment for playing JJ and JJM is to use a virtual machine (virtualbox) and windows XP or Windows 2000 (make sure Flash and DirectX is installed there too)

Sfaizst