I can access excel file from local machine, but I cannot open excel from

share folder using C# and .net 2? The returned message is: The Microsoft Jet database engine can not open the file <excel file name>. You need permission to view its data. My connection string is :
string strConn="Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+sfile+";"+"Extended Properties=Excel 8.0;"
where sfile="\apiaddress\sharefolder\excelfilename"