Excel Call was rejected by callee Error

Question

I've written a vbs that essentially opens Excel in the background, runs a macro on it and then saves it by appending the value of a cell to it's name. However, and this only occurs sometimes, I get a error on the bolded lines...

Line: 23
Char: 3
Error: Call was rejected by callee.
Code: 80010001
Source: (null)

Option Explicit

ExcelMacroExample

Sub ExcelMacroExample() 

  Dim objExcel  
  Dim objApp  
  Dim objWorkbook
  Dim objSheet
  Dim SI
  Dim scriptdir
  Dim oFSO
  Set oFSO = CreateObject("Scripting.FileSystemObject")
  scriptdir = oFSO.GetParentFolderName(WScript.ScriptFullName)

  Set objExcel = CreateObject("Excel.Application")
  Set objWorkbook = objExcel.Workbooks.Open(scriptdir & "\SCORECARD.xlsm")

  objExcel.Run "RefreshConns"
  WScript.Sleep 90000 

  Set objSheet = objWorkbook.Worksheets("Cover")

  SI = objSheet.Cells(4, 2).Value

  objExcel.ActiveWorkbook.SaveAs scriptdir & "\Scorecards\" & "SCORECARD_" & SI & "_" & Year(Now()) & Month(Now()) & Day(Now()) & "_" & Hour(Now()) & Minute(Now()) &".xlsm", 52

  objExcel.ActiveWorkbook.Close
  objExcel.Quit   

  MsgBox("Successfully generated profiling scorecard.")

End Sub