John,

My suggestion left something out. This should work.
oExcel.ActiveChart.SetSourceData(.Sheets("cheqsale").Range("AB4:AB8"),xlColumns)

You may need to add this line too.
oExcel.ActiveChart.Location(xlLocationAsObject,"cheqsale")

Using WITH/ENDWITH will be better.

WITH oExcel.ActiveChart
.SetSourceData(.Sheets("cheqsale").Range("AB4:AB8"),xlColumns)
.Location(xlLocationAsObject,"cheqsale")
ENDWITH

Sorry I did not notice the missing period.

Tom Molloy