CELL REFERENCE

I have 2 sheets in 1 workbook. In the second sheet I use a cell reference to a cell in the first sheet(ie,DATA!G1). It works fine on the setup; however, when I change, copy an paste or delete the line on which the data is located in the first sheet I get a #REF error in the second sheet.

I remember many years ago I was able to do that and the data in the second sheet appeared correctly each time I changed line 1 in the first sheet.