Execution of Macro Stops

I am facing a peculiar problem while running a macro in Excel 2007. This macro is being run in an excel file named "Test.xlsm". My macro code is as under -

Sub Macro1()
'
' Macro1 Macro
'

    Workbooks.Open FileName:="C:\Data\LIB\AuditMasters.xlsx"    => Macro execution stops here.

    Windows("Test.xlsm").Activate

    Range("B8").Select

    ActiveCell.FormulaR1C1 = _
        "=VLOOKUP(RC[-1],[AuditMasters.xlsx]BranchDirectory!R2C1:R1500C2,2,FALSE)"

    Windows("AuditMasters.xlsx").Activate

    ActiveWorkbook.Close

    ActiveWorkbook.BreakLink Name:="C:\Data\LIB\AuditMasters.xlsx", Type:= _
        xlExcelLinks

End Sub

Now the problem is that the code runs without any problem in the debug mode. But when I execute the code using the shortcut key assigned to the macro, the program stops after opening the file in line no. 1.

Can someone suggest a solution to this problem.