If you use Intent MIDlet Manager and re-install the gmail app it will work. I use the .1034 version of MIDlet mgr.
http://forum.xda-developers.com/showthread.php?t=286604
as a final tip, the 1.0.0 version of GMail works great on the HTC Touch and it runs quite a bit faster than 1.5.x. The 1.0.0 version has all the features that matter to me.
I installed it using the following url and am very happy with performance now:
http://www.gmail.com/app/v1.0.0/en/g...nced_MIDP2.jad