Code seems to be caught in Loop!!

I think my code (VBA/ArcObjects) is stuck in a loop and won't end. I hit the Map button on my dialog box and nothing happens???? Please let me know where I went wrong.

Private Sub cmdMap_Click()

Dim cboStations As String
Dim cboDistrict As String

Dim mapDocument As IMapDocument
Set mapDocument = New mapDocument

If mapDocument.IsPresent("K:\TASS\4_MAPPING_DATA_SUPPORT\Traffic_Mapping\District_Maps\2012\Abilene\Abilene_Base_Map.mxd") Then
mapDocument.Open ("K:\TASS\4_MAPPING_DATA_SUPPORT\Traffic_Mapping\District_Maps\2012\Abilene\Abilene_Base_Map.mxd")
End If

End Sub