Server Threw an Exception on Workbook.Close

[jonpyne]

I have a simple MS Word macro that opens up MS Excel files, grabs tables or graphs and inserts them into the MS Word file. It works fine on my computer (MS Windows 2000, MS Office 2000 SP3) and some of my colleagues' (MS Windows 2000/XP, MS Office 2000 SP3), but produces a runtime error on others' (MS Windows XP, MS Office 2000 SP3).
On trying to .Close certain files, we get a "Server threw an exception" error: -2147417851 (80010105) on some systems.
Any ideas?
thanks

I can provide more detailed code if need be, but this is the framework ...

' ... Subroutine
Public objExcel As Excel.Application '... have tried late-binding, with Object
Public objWorkbook As Excel.Workbook
Private ExcelRunning As Boolean

Sub HookExcelObject()
    On Error GoTo ExcelNotRunning
    ExcelRunning = True
    Set objExcel = GetObject(, "Excel.Application")
    Exit Sub
ExcelNotRunning:
    ExcelRunning = False
    Set objExcel = CreateObject("Excel.Application")
End Sub

Sub UnhookExcelObject()
    If Not ExcelRunning Then
        objExcel.Quit
    End If
    Set objExcel = Nothing
End Sub

' ... Main Module, behind a form
Call HookExcelObject

strFile = "c:\file_1.xls"
Set objWorkbook = objExcel.Workbooks.Open(FileName:=strFile, Updatelinks:=False, ReadOnly:=True)
objWorkbook.Sheets(strSheet).Range(strRange).Copy
objWorkbook.Close SaveChanges:=False

strFile = "c:\file_2.xls"
Set objWorkbook = objExcel.Workbooks.Open(FileName:=strFile, Updatelinks:=False, ReadOnly:=True)
objWorkbook.Sheets(strSheet).Range(strRange).Copy
objWorkbook.Close SaveChanges:=False ' <<< CRASH, BANG, WALLOP!

Set objWorkbook = Nothing
Call UnhookExcelObject

 

[jonpyne]

Sorry to throw this in your face again.
If I halt the code at the .Close line, I can probe the two objects fine.

? TypeName(objExcel), TypeName(objWorkbook)
Application   Workbook
? objExcel.ActiveWorkbook.Name, objWorkbook.ActiveSheet.Name
my_workbook.xls   my_Sheet
objExcel.Visible = True
objWorkbook.Activate
objWorkbook.Close SaveChanges:=False
<BOOOOOOOM>

objWorkbook.Saved = True
objWorkbook.Close
<BOOOOOOOM>

objExcel.Visible = True
objWorkbook.Close(False)
<BOOOOOOOM>

Does anyone have any ideas at all?