Take a look at our FAQ: Reporter and you’ll find this entry.
I’m surprised that the “>=” even works – perhaps you’re on a newer version? Traditionally, the SUM (WHERE…) required that the operator needed to be an equal sign.
And, the operand to the right required a constant or a variable – no functions. So try creating a new variable called whatever you want, I"ll pick “X”:
X =ToNumber(SubStr(UserResponse (“Query 1” , “Enter Year & month YYYY/MM”) ,1 ,4))
and then change your SUM() Where (= X)
Anita Craig 
(BOB member since 2002-06-17)