I don't think you have a compatibility issue; I think you're going through what I did. When I got my D60, I had a lot of consumer lenses which had worked well enough on my Elan7. But somehow the D60 picked up so much more detail that the lenses didn't work well at all on it.
I'm not saying I have all pro lenses (I have a mix of high end consumer and pro lenses that works for me) or that you should. But you might want to consider a lens a big higher in performance rating. Here's a site that rates lenses:
http://www.cmpsolv.com/photozone/lsurveyEOS.htm and, if you sort by performance, you'll see your lens is quite near the bottom of the ratings list.
You might think about getting a 28-135/3.5-5.6 IS. It's an excellent all-around lens and the image stabilization is a very nice feature. Best of all, it "plays" well with the Canon digitals.
Gorham