Excel 2003 :: Do Until IsEmpty Looping

Excel 2003. I believe I've got everything working in the code up until:

Code:
If rnGx = rnGy Then

It loops once and then "Run-time error '424': Object Required" for the code above.

Code:
Sub test1()
Dim rnGx As Range
Dim rnGy As Range
Dim i As Long
Dim xNum As Integer
Dim yNum As Integer
i = 2
Set rnGx = Cells(i, 2)

[Code] ....

In case I'm way off, I'm trying to get the code to do the following:

Look for identical entries in column bw here duplicates exist, sum the corresponding column d values into one of the existing columns delete the remaining duplicate do this until there are no matches.

Column b is sorted ascending, so any matches should be next to each other. as I'm writing this, though - I realize that if there are triplicates or more in column B, this would need to be run more than once.