Here it is...

F G H I
12/31 0040
01/01 01/02
12/31 01/01
0900 2059 * *
2100 0859 * *

Columns F and G hold the data I have to sort through using the SUMPRODUCT
function. H and I hold the "categories" or ranges that column G need to fall
between to be classified under the corresponding date. In
other words, the entry in F1/G1 would be counted for the "2100/0859"
category...

This is the general formula I was given to use...
=SUMPRODUCT(--(Sheet1!$A$2:$A$20=B$1),--(Sheet1!$B$2:$B$20=--(LEFT($A2,2)&":"&MID($A2,3,2))),--(Sheet1!$B$2:$B$20<=--(MID($A2,6,2)&":"&RIGHT($A2,2))))

I cannot figure out why this won't work...please help!