Well, the thing is, your Count statement isn't actually qualified.  Your statement "count ({insertbk.adnumbr})" counts all the ads, regardless of what your If condition is.

Move the If..Then structure inside your calculation, and try:

SUM (IIF({insertbk.dateins} in {?startdaterange} to {?stopdaterange}, 1,0))

What this does is evaluate the date for each record.  If it is within the date range, it adds it to the sum (by evaluating to 1).  If not, it ignores it (by evaluating to 0, which obviously doesn't increase the sum).

You can also try grouping your report on the {insertbk.dateins} field, and choosing "for each year" in the group options.  You can then simply put a Count in the group header.  But, based on the way you are using parameters, that may not work out quite right for you.