unwanted renumbering of an attached file

[SisMary]

Hi,

I am using office2000/win2k and on opening directly one specific excel file
which name ends with a figure (for example 834.xls ) under outlook (double
click on the icon of the attached document) I get a renumbering of this
excel file (the excel workbook title shows 8341.xls)

A normal opening (save attached file then double-click on the resulting
file) does not generate any renumbering

?????????????

Thx in advance