OLEDB Connection.Open() Exception - Failure in Creating File

When automating in Thin Client Machines an exception is thrown while opening the
OLE DB Connection as "Failure in Creating File". Connection string is given correctly but don't know why this happens. it would be helpful if appropriate solution is given.

This the connection string which i used.

connectionstring = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + drivename + "\" + variable1 +"\" + variable1+ "-DownLoadedData.xls" + ";Excel 12.0 Xml;HDR=YES";