ref error

in the attached spread sheet data is pulled in from a folder containing individual spread sheets by selecing from the drop down list. it works very well. when i changed the formula in column o from =IF(AND(E6<=K7),-1,IF(AND(D6>=J7),1,0)) to =IF(AND(E7<=K8),-1,IF(AND(D7>=Jk),1,0)) i get a ref error each time i update the spreadsheet with new data. can any one solve this. funny thing is when i change the formula to =IF(AND(E7<=K7),-1,IF(AND(D7>=J7),1,0)) it works fine .hope you can help