=IF(ISBLANK(B7),"",INT((B7/$B$9)*A17))

I get the little triangle at the top left corner of the cell which contains
the formula above, and it says "Inconsistent Formula Error".

If B7 is empty, I want to leave the receiving cell empty, Else write the
respective number. If I just have =INT((B7/$B$9)*A17) in the receiving
cell, that places a 0 (zero) in the respective cell. I need that cell to
remain empty if there is no number to calculate in B7. What is the correct
formula to do this?

Thanks,
Rich