an alternative approach could be using Excel as the server applicaton controlling Autocad
in that case the following could be of any help
1) insert an event handler for selection changes in your sheet module
2) have it send the selected cell value to Autocad command line via the "prompt" method of the "Utility" object
something like this
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Rows.Count = 1 And Target.Columns.Count = 1 Then ThisDrawing.Utility.prompt Target.value
End Sub