|Your formula works fine for me.|
With this data, your formula returned 5 (3 from Row 4 plus 2 from Row 6)
F ... J K L M
3 1 1 2
4 13 1 2
5 3 1 2
6 13 2
However, if one of the cells in J:M is not a number, then you will get a #VALUE error.
For example, enter Tom in J4 and the formula will return #VALUE. Even a space will cause the error, so make sure that any empty cells are really empty.
If you are still having problems, the please click on the following line, read the instructions on how to post example data in this forum and then post a short example of your data like I did above.
Click Here Before Posting Data or VBA Code ---> How To Post Data or Code.