The only time you see that warning is when a program uses 3D. In case of DRI drivers it can mean that libGL was unable to load the 32-bit dri module for your card. There used to be an ubuntu issue regarding the 32-bit dri path e.g. it used /usr/lib/dri instead of /usr/lib32/dri. Not sure if that issue is still around. If it is try 'export LIBGL_DRIVERS_PATH=/usr/lib32/dri' and then run wine from that terminal.
