Why can't I use sheets of an excel file after uploaded by fileupload in firefox?

[Albert bara]

in this place happen error.
con.ol_cn.Open( )
con.ol_cm.Comma ndText = "SELECT * FROM [Sheet1$]"
con.ol_cm.Execu teNonQuery()
<error
The Microsoft Jet database engine could not find the object 'Sheet1$'. Make sure the object exists and that you spell its name and the path name correctly./>