SUMPRODUCT - where range has formula returned "" blank cells

In the table below, the blank cell D1 is not an empty cell, but driven from a formula such as =IF(G2="","",G2)


x y z x
1 1 1
2 1 3 3
3 3 4 5

When trying to use the formula =SUMPRODUCT((A2:D4)*(A1:D1="x")) I get #VALUE!

Is there any way to make this calculation work and ignore the blank cells