Open an excel file from a windows service under Windows Vista

Hi.

I create a windows service. In its start method I try to open an excel file. I use the following code:

Excel.Application excelApplication = new Excel.ApplicationClass();
object _missingParam = Missing.Value;
Excel.Workbook _excelWorkbook = excelApplication.Workbooks.Open(filename,0, 0, _missingParam, _missingParam, _missingParam, _missingParam, _missingParam, _missingParam, _missingParam, _missingParam, _missingParam, _missingParam);

On windows XP when I start the service this works fine.

But on windows Vista I get the following error:
System.Runtime.InteropServices.COMException (0x800A03EC): Exception from HRESULT: 0x800A03EC.
at Excel.Workbooks.Open(String Filename, Object UpdateLinks, Object ReadOnly, Object Format, Object Password, Object WriteResPassword, Object IgnoreReadOnlyRecommended, Object Origin, Object Delimiter, Object Editable, Object Notify, Object Converter, Object AddToMru)
at SPARTAServ.SPARTAService.OnStart(String[] args) in e:\work\spartaserv\spartaservice.cs:line 243

Please help. Thanks.

With your Visual Studio should come an error lookup utility. Put the HRESULT value in there and tell us what it means.

Also, Google gives some results that might help:
http://www.google.at/search?q=hresul...ient=firefox-a