The QR Count columns command returns the number of columns present in the Quick Report area.
If you pass an invalid area number, the error -9850 will be generated.
The following code retrieves the column count and inserts a column to the right of the rightmost existing column:
$ColNb:=QR Count columns(MyArea)
QR INSERT COLUMN(MyArea;$ColNb+1;->[Table 1]Field2)