Wayne,
had a nice day at work?
I changed your code a bit, because i need the return value to pass it in a function:
For i = 1 to 6
If IsNull(Me.Controls("txtStudent" & CStr(i)) Then
textboxX = Me.Controls("txtStudent" & CStr(i)) End If
Next i
MoveSingleItem "lstCursist", " texboxX"
(or can...