Formula correction HELP!!!
 

I've got this formula, What I need to do is trap for when there is no data,
when there is no data show either "Empty String" or 0, instead of the dreaded
#Value! error message. Here is the formula: =SUMPRODUCT(--('A
Shift'!$A$4:$A$120="A"),--(TEXT('A Shift'!$B$4:$B$120,"mmm-yy")="Mar-05"),('A
Shift'!$D$4:$D$120))/SUMPRODUCT(--('A Shift'!$A$4:$A$120="A"),--(TEXT('A
Shift'!$B$4:$B$120,"mmm-yy")="Mar-05"),"",(--('A
Shift'!$A$4:$A$120="A"),--(TEXT('A Shift'!$B$4:$B$120,"mmm-yy")="Mar-05"),('A
Shift'!$D$4:$D$120))/SUMPRODUCT(--('A Shift'!$A$4:$A$120="A"),--(TEXT('A
Shift'!$B$4:$B$120,"mmm-yy")="Mar-05"))

The call for an empty string, I believe is where it's falling out, not sure!