As I understand the situation,
Search Engines do not have any trouble with the ASP suffix, it is the ? that follows that causes the problem. The "?" signifies that the content of the page could change at any time depending on the cirteria specified after the "?". Hence, and engine says, this could create an "infinite number of possibilities"
Imagine if you will coming to a crossroad and asking your navigator which way to turn. Your navigator then says "Well if you want to go to London, turn left, but if you want to got to Paris, straight ahead, but if you want to go to Milan, turn right, but if you want to go to Sydney, turn hard right, but if you want to go to ....."
Thats the same as the "?".
One solution is to write scripts that rewrite the dynamic pages as static pages, either on the fly or on a schedule. (this is beyond me at the moment..)
Another solution is to set up static doorway pages as engine suggests, and these can be asp pages.
Lets suppose you are setting up a directory. You would need to set up pages for each section of the directory that automatically gets the first set of information and sets up links for a true dynamic page that retrieves the subsections. Or a page that automatically gets the first 10 results with a link for the next ten results. Of course you decide how far down into the directory you go with your "autodoorway pages". It is important however that these intro pages do not have the "?" and that the information qualification information is hard coded into the ASP code.
The analogy is coming to a crossroad and seeing a sign that says "Turn Left for UK cities, Straight ahead for European Cities, Right for Asian Cities, and Hard Right for Australian cities and prepare for a long swim...."
After travelling down the UK road a little you then come to a crossroad where the navigator asks "London? Brmingham? Glasgow? etc"
Follow? Help? Hope so.