VBA error - Object Not Found

using 2007 SP3

Below is a macro that calculates the DCMA BEI.  It works great on my files.  but when I take it to another machine (same setup, same MS project app etc) - it bombs.

the code line that fails is:   tbActualFin = Application.ActiveSelection.Tasks.count

- which works fine on my machine but not on my colleague's

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Sub Calc_BEI()
Dim tbActualFin As Long
Dim tbShouldFin As Long

'create filter for Actual Finish
    FilterEdit Name:="Actual Finish BEI", TaskFilter:=True, Create:=True, OverwriteExisting:=True, FieldName:="Actual Finish", _
    Test:="does not equal", Value:="NA", ShowInMenu:=False, ShowSummaryTasks:=False
    FilterEdit Name:="Actual Finish BEI", TaskFilter:=True, FieldName:="", NewFieldName:="Baseline Duration", Test:="is greater than", Value:="0", Operation:="And", ShowSummaryTasks:=False
    FilterEdit Name:="Actual Finish BEI", TaskFilter:=True, FieldName:="", NewFieldName:="Summary", Test:="equals", Value:="NO", Operation:="And", ShowSummaryTasks:=False
    FilterApply Name:="Actual Finish BEI"

'select data and count
 SelectTaskColumn Column:="Name"
    tbActualFin = Application.ActiveSelection.Tasks.count

'set variable to status date
tbProjStart = DateFormat(ActiveProject.StatusDate, pjDate_mm_dd_yy)
'create filter for baseline finish
 FilterEdit Name:="BL Finish BEI", TaskFilter:=True, Create:=True, OverwriteExisting:=True, FieldName:="Baseline Finish", _
    Test:="is less than or equal to", Value:=tbProjStart, ShowInMenu:=True, ShowSummaryTasks:=False
    FilterEdit Name:="BL Finish BEI", TaskFilter:=True, FieldName:="", NewFieldName:="Baseline Finish", Test:="equals", Value:="NA", Operation:="Or", ShowSummaryTasks:=False
    FilterEdit Name:="BL Finish BEI", TaskFilter:=True, Parenthesis:=True, FieldName:="", NewFieldName:="Duration", Test:="is greater than", Value:="0", Operation:="And", ShowSummaryTasks:=False
    FilterEdit Name:="BL Finish BEI", TaskFilter:=True, FieldName:="", NewFieldName:="Summary", Test:="equals", Value:="No", Operation:="And", ShowSummaryTasks:=False
    FilterApply Name:="BL Finish BEI"
       
'select data and count
 SelectTaskColumn Column:="Name"
    tbShouldFin = Application.ActiveSelection.Tasks.count

FilterApply Name:="All Tasks"

'calculate BEI
tbBEI = Round(tbActualFin / tbShouldFin, 2)

'display in message box
MsgBox "Status Date = " & tbProjStart & vbCrLf & vbCrLf _
& "Actual Finish Count =" & tbActualFin & vbCrLf _
& "     Baseline Count = " & tbShouldFin & vbCrLf & vbCrLf _
& "BEI = " & tbActualFin & " / " & tbShouldFin & " = " & tbBEI

End Sub

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anybody have a clue?

GMAN