Your code has this line that assigns a value to INSERTPT:
INSERTPT = ActiveCell.Value
.... and later, an IF statement that compares a cell value to INSERTPT:
If Cells(i, 1).Value = INSERTPT Then

Is it possible the value in Cells(i, 1).Value never equals INSERTPT?

The other thing I notice is this line
For i = iLastRow To 1 Step 1
In order to get this structure to run, I had to change it to this:
For i = iLastRow To 1 Step -1
Is that a similar problem for you?