You should always post what you've tried that doesn't work. I'll take a stab at it, but could be suggesting something you've already tried. The cause may be you are not using the proper syntax for referencing subform controls. There is a hierarchy for this. It is
[Forms]![Main form name]![subform control name].[Form]![control name on subform] Note: subform control name is NOT about the name of the subform; rather it is the name of the control that contains the subform. Too often, Access wizards give form/report controls the same name as fields or subform controls the same name as the subform. If your control and subform have the same name, so be it, but one should always fix this duplication that the wizard creates.
I don't use macros, and since the GoToControl is a macro action, I presume you are. In that case I believe your action will apply to the object that has the focus, which in your case might be the parent form. You can try the syntax I provided where it asks for the control you want to move to, substituting your own object names and see if it works. If the fact that the parent form has the focus is an issue, you can use the RunCode action to execute a little sub in a standard module:
Public SetTheFocus ()
[Forms]![Main form name]![subform control name].[Form]![control name on subform].SetFocus
End Sub
If that works, you could replicate it for any control on that subform as needed.
PS: if you need to post a db, you have to zip it. You should compact/repair your db before doing so. Usually that gets the size down to where you can post it.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.