"Doesn't work" doesn't help much as I always say. If you were to say "I get a number instead of a name" then we'd ask if GrpOS is a combo box, in which case you're likely passing the bound (ID) field to the expression and not the name you see in the combo. Then again, you would have to have said that you're stepping through the code (a very basic trouble shooting procedure) to even know that you're passing a number as criteria to DLookup. Less powerful but still helpful is a message box to tell you what's in the control before you try to use it.
To me, the most intriguing thing is, IF the control on the form is a combo and FLname and Email are in the same table, then why not just add Email as a column to the combo?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.