Problem with SQLXML BulkLoad from .NET Application

[=?Utf-8?B?Sm9iIExvdA==?=]

I am using BulkLoad from .NET application as follows

SQLXMLBULKLOADLib.SQLXMLBulkLoad4Class obj = new
SQLXMLBULKLOADLib.SQLXMLBulkLoad4Class();
obj.ConnectionString =
"Provider=SQLOLEDB;Server=serverName;Database=dbNa me;Integrated
Security=SSPI";
obj.ErrorLogFile = Application.StartupPath + @"\Error.log";
obj.IgnoreDuplicateKeys = true;

try
{
obj.Execute(Application.StartupPath + @"\Schema1.xsd",
Application.StartupPath + @"\Data1.xml");
obj.Execute(Application.StartupPath + @"\Schema2.xsd",
Application.StartupPath + @"\Data2.xml");
}
catch (Exception ex)
{
throw ex;
}

I get following error when I run my application:

InvalidCastException was unhandled by user code.

Unable to cast COM object of type 'SQLXMLBULKLOADLib.SQLXMLBulkLoad4Class'
to interface type 'SQLXMLBULKLOADLib.ISQLXMLBulkLoad4'. This operation failed
because the QueryInterface call on the COM component for the interface with
IID '{88465BA7-AEEE-49A1-9499-4416287A0160}' failed due to the following
error: No such interface supported (Exception from HRESULT: 0x80004002
(E_NOINTERFACE)).

When I run the same code in a Console application it works alright. In my
application the code is executed on a Background thread, could that be cause
of exception? Please help.

Thanks