OK, same problem here although not quite this severe. What I have fouind is that if you go into the Settings/About Phone/Battery use/you will see the list of programs that have been using your battery.
I downloaded the Adobe Reader for my phone, as you have to have this now in this day and age. Once I view an Adobe file the battery drain starts. I can not get it to stop no matter what I do, I have clered the cache in the adobe program (Settings/About phone/Applications/Manage Applications/Adobe/Clear Cache and Force Quit under the same menu) forced quit Adobe everything to no avail. The Advanced task Killer does not work either.
I have uninstalled Adobe and re-installed it thinking that it was just maybe a botched down-load. Same thing.
Check to see if this could be the cause. I am not sure what the cure is as we have to use Adobe but anyway juat trying to help you out here.