Calling SSIS package from C# Windows Service Fails

Question

Hi All.
I've got an SSIS package that reads from an Excel file and populates a database. The Excel file location gets passed in to the package as a variable. Also the Protection Level of the package is set to EncryptSensitiveWithPassword.
This all works fine when I run the package from Visual Studio or using DTEXEC. When I try to run it from a C# Windows Service though I get the following exception:
SSIS Error Code DTS_E_OLEDBERROR.  An OLE DB error has occurred. Error code: 0x80004005.
An OLE DB record is available.  Source: "Microsoft Office Access Database Engine"  Hresult: 0x80004005  Description: "The Microsoft Office Access database engine cannot open or write to the file ''. It is already opened exclusively
by another user, or you need permission to view and write its data.".
SSIS Error Code DTS_E_CANNOTACQUIRECONNECTIONFROMCONNECTIONMANAGER.  The AcquireConnection method call to the connection manager "Input Excel Connection" failed with error code 0xC0202009.  There may be error messages posted before this
with more information on why the AcquireConnection method call failed.
Dedupe Worksheet failed validation and returned error code 0xC020801C.
One or more component failed validation.
There were errors during task validation.
The windows service runs with LocalSystem account and the following code is used to call the SSIS Package:
                Application app = new Application();
                Package package = null;
                app.PackagePassword = "*******";
                //Load the SSIS Package which will be executed
                package = app.LoadPackage(@"C:\Projects\DataDedupeMatch\DataDedupeMatch\DataDedupe.dtsx", null);
                //Pass the varibles into SSIS Package
                package.Variables["User::FilePath"].Value = e.FullPath.Replace(@"\\", @"\");
                Microsoft.SqlServer.Dts.Runtime.DTSExecResult results = package.Execute();
I would really appreciate if someone could help me out with this.
Thanks in advance,
Deon

Answer 1

Instead of hosting the SSIS runtime in your service, you should use a separate host process for your SSIS package.  You're using the Office drivers, which aren't designed or supported for running in long-lived unattended processes like a Windows Service. 
You can use your own SSIS hosting code, or just use dtexec.exe to host your package.  In either case you would start the child process with
Process.Start. 
David
David http://blogs.msdn.com/b/dbrowne/