Not an EXCEL whizz, and not able to view your screenshot from work, but ..
Do you want one cell in a tabbed worksheet to be a total field for one or more cells in another worksheet in the same EXCEL file ?
- highlight the cell you want to be the total and hit F2 to edit the contents. Key in =SUM(), and position the cursor between the brackets.
- click on the tab of the second worksheet and highlight the cell, or range of cells, to be totalled.
- click the 'green tick' to commit the change
This works for me in EXCEL 2003.
HTH