divx issues when encoding in virtualdub

i have a 561 mb file ..it is a tutorial. it is only 22 mins long. i am trying to use virtual dub and divx to get it down in file size. I know a site and will email anyone that wants it ....where it has same kind of tuts and his file size is around 100 mb ...I need help bad and willing to pay for it ..if there is a proven method. i have talked to him and he uses vdub to do it and does several passes. I am getting something wrong. i am willing to pay like i said but this is out of my own pocket. hell i willing to offer divx to custom make something if not too far out of my price range ....

mmoore@smoothstone.com is my msn name ...