=IFERROR(INDEX('Overview - 2014'!$G$15:$G$5000, SMALL(IF(('Overview - 2014'!$B$15:$B$5000=$B$3)*(('Overview - 2014'!$C$15:$C$5000>=DATE(2014,4,28))*('Overview - 2014'!$C$15:$C$5000<=DATE(2014,5,27)))*('Overview - 2014'!$J$15:$J$5000="Yes"),ROW('Overview - 2014'!$B$15:$B$5000), ""), ROW(A1))), "")

I appreciate this being ridiculously vague and I understand if you want to see a working example, but can anyone tell me (this is Ctrl + Shift enter formula) why it produces one number in that given month, but when I drag it down it produces "0".

Usually it will return what's called a "CJ number" or CJ12345 but instead it will only populate one of the many CJ numbers I am looking for (simply put, the answer I am wanting from this formula) and the rest will be "0"'s (if applicable)...

I don't know why it is returning a "0" and not the stupid CJ number! It's getting the first row right and after I drag the formula down it won't work :s