Requerying values in a subform after updating combo box in main form

I'm fairly new to Access, and was hoping somebody would be able to help me with an issue I've encountered.

Within my main form I have a combo box called "workgroup." Also in the main form is a subform called "sfrmSubmissionRecords," and within this subform is a combo box called "covermemo."

Each cover memo is assigned to a specific workgroup, so my intention is for each time a new workgroup is selected from the dropdown, the covermemo combo box in the subform becomes populated only with the covermemos associated with that workgroup. I'm almost finished except for the final step when I try to make the values regenerate...Access says that can't find the referenced form "sfrmSubmissionRecords"

This is the code that I'm using:

Private Sub cmbWorkgroup_AfterUpdate()
Forms![sfrmSubmissionRecords]![cmbCovermemo].Requery
End Sub

Thanks very much for your help!

Requerying values in a subform after updating combo box in main form