I ran into something similar recently.  Use SetKey instead of Find (or your Lines object is not pre-filtered).

retVal = oSOrder.Find(OrderNo)

Or SetBrowseFilter for your Lines object.

Edit: oh... and you have to Write from the SO header object too.

Can you help me with the syntax on the write line? It looks like I have everything else working. Thanks for the info. It helped.

After your loop:

retVal = oSOrder.Write()

Ok, I've got that, now I'm running into another issue. I know it's related to the same thing, but not sure how to resolve it. My Line details are still not zeroing into the correct order. Also, it seems to be ignoring the move next statement. I also tried a do until and that didn't seem to work. Here's my code again with some updates.

if oSession.CompanyCode = "TTT" then

Dim oSOLines
Dim oSOOrder
OrderNo = ""
OrderNo1=""
Item = ""
oSOLines = ""
oSOrder = ""
PickQty=0

'*** Update and Insert Pick Qty to 0 ***
retVal = oBusObj.GetValue("SalesOrderNo$", OrderNo)
retVal = oSession.SetProgram(oSession.LookupTask("SO_SalesOrder_ui"))
oSOrder = oSession.GetObject("SO_SalesOrder_bus")
Set oSOrder = oSession.AsObject(oSOrder)
Set oSOLines = oSOrder.AsObject(oSOrder.Lines)
retVal = oSOrder.SetKeyValue("SalesOrderNo$",OrderNo)
retVal = oSOLines.SetBrowseIndex("KPRIMARY", OrderNo)
retVal = oSOLines.MoveFirst()
retVal = oSOLines.GetValue("SalesOrderNo$", OrderNo1)
retVal = oSOLines.GetValue("ItemCode$", Item)
retVal = oSOLines.GetValue("UDF_PICK_QTY", PickQty)
retMsg = oSession.AsObject(oSession.UI).MessageBox("", OrderNo1 & " " & Item & " Pick Qty " & CStr(PickQty))

retVal = oSOLines.SetValue("UDF_PICK_QTY", PickQty) 'set the qty to 0
retVal = oSOrder.Write()

retVal = oSOLines.MoveNext()



end if 'end company GLT

SetKey, not SetKeyValue and the SetBrowseIndex for your Lines object is not necessary.

You need a loop to scroll through multiple lines.

There are a few things missing in your script:

1) you need to do oSOrder.SetKey() after SetKeyValue.

2) The SetBrowseIndex call is not needed

3) You need a loop to loop through your lines, test EOF like in your original script 

4) you need to do oSOLines.Write() after setting the UDF to write the line record

5) after setting UDF on all lines, do oSOrder.Write() once at the end to write the order

Thanks Natasha. I did all of that. I'm still not able to point into the correct order in the lines. Instead, it's reading through all the lines. I have temporary code in there to bypass if the order number is not correct, but this won't work in the final product. Also, the write is still not working.

Dim oSOLines
Dim oSOOrder
OrderNo = ""
OrderNo1=""
Item = ""
oSOLines = ""
oSOrder = ""
PickQty=0

'*** Update and Insert Pick Qty to 0 ***
retVal = oBusObj.GetValue("SalesOrderNo$", OrderNo)
retVal = oSession.SetProgram(oSession.LookupTask("SO_SalesOrder_ui"))
oSOrder = oSession.GetObject("SO_SalesOrder_bus")
Set oSOrder = oSession.AsObject(oSOrder)
Set oSOLines = oSOrder.AsObject(oSOrder.Lines)
retVal = oSOrder.SetKeyValue("SalesOrderNo",OrderNo)
retVal = oSOrder.SetKey(OrderNo)
retVal = oSOLines.MoveFirst()
Do Until cBool(oSOLines.Eof) = True
retVal = oSOLines.GetValue("SalesOrderNo$", OrderNo1)
if OrderNo = OrderNo1 then
retVal = oSOLines.GetValue("ItemCode$", Item)
retVal = oSOLines.GetValue("UDF_PICK_QTY", PickQty)
retMsg = oSession.AsObject(oSession.UI).MessageBox("", OrderNo1 & " " & Item & " Pick Qty " & CStr(PickQty))

retVal = oSOLines.SetValue("UDF_PICK_QTY", PickQty) 'set the qty to 0
retVal = oSOLines.Write()
End IF
retVal = oSOLines.MoveNext()
Loop

retVal = oSOrder.Write()

Move your Set oSOLines command to after your oSOrder.SetKey line.

Does it successfully loop through the lines?  Does you message box pop up?

You don't need to pass in OrderNo to SetKey() since you already did SetKeyValue.

You can check retVal of each call. If it is 0 (failure), check LastErrorMsg eg. oSOLines.LastErrorMsg.

It does loop through the lines, but it starts with the first sales order in the system and doesn't point to the current order number. I'll check the oSOLines.LastErrorMsg when retVal is not equal to 1 and see if I can figure it out from there. Thanks for your help. If you see anything else that I'm doing wrong, I'm still open for suggestions... Thanks again.