QueryTable Error

This is a snippet of code that is bothering me. I have Query Tables and Pivot Tables. I'm trying to refresh the query tables first, and then refresh the pivot tables because the pivot tables pull data from the query tables.

I keep receiving this error: "Run-Time Error 91: Object Variable or With Variable Not Set"

Debug points to the last line of this code snippet.

Private Sub CommandButton2_Click()
    Worksheets("MAS (Sales Lines)").Select
    Selection.ListObject.QueryTable.Refresh BackgroundQuery:=False
    Worksheets("MAS (GL Acct)").Select
    Selection.ListObject.QueryTable.Refresh BackgroundQuery:=False
End Sub

Any help is appreciated!

-David