Agree with Bob that you should have a tblProjectMembers. To get your code working maybe try this (note you say the text box name is TeamWork yet in code you use TeamWorktxt):
Code:
Private Sub WT_Quality_Click()
If Me.WT_Quality = -1 And Nz(Me.TeamWork,"") = "" Then
Me.TeamWork = DLookup("[Name]", "[Team_Work]", "[Departament]= 'Quality'")
ElseIf Me.WT_Quality = -1 And Nz(Me.TeamWork,"") <> "" Then
Me.TeamWork = Me.TeamWork & " " & vbCrLf &DLookup("[Name]", "[Team_Work]", "[Departament]= 'Quality'")
Else
Me.TeamWork= "Test failed"
End If
End Sub
Cheers,
Vlad