I am running this line of code

case !empty(Thisform.txtpg_no.value)
WITH ThisForm.txtPG_NO
do case
case !seek(.value,"pgappl","ONLYPGNO")and i am getting this error:
endcase

"Object is not contained in a FORMSET"
I have no clue what this is referring to since I am not referencing a formset at all.
Does anyone have any help on this????
Thanks.
Shevy