Problem while Writing to Remote Location in a .net Thread

hi

i am having problem when i am trying to write something on remote location using .net thread.
e.g. i have a central location letsay MachineName|MachineIP/SharedDrive.
and i am creating a thread on click of a button which i need to write some information on that location.

i have also added a node <identity impersonate="true" userName="Domain\User" password="*******"/> in web.config of my application.

and i have also given credential in <Machine.Config>--<ProcessModel enable="true" UserName="SameInWeb.Config" password="SameInWeb.Config">

but it is giving the following exception:
The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you.

below is my method which i am calling on a separate thread.
private void WriteSomeThingToRemoteLocation ()

{
FileStream fileStream = null;
BinaryFormatter binaryFormatter = null;
System.Object systemObject = null;
System.Object obj = new object();
lock ( obj )
{
string _contractLocaterKey = Guid.NewGuid().ToString().Replace( "-", "" );

string fullPath = @"\\MyMachineIP\SharedDrive" + "\\" + _contractLocaterKey + ".dat";
try
{
fileStream = new FileStream( fullPath, FileMode.CreateNew, FileAccess.Write );
binaryFormatter = new BinaryFormatter();

systemObject = new object();
systemObject = "Hello this is testing1";
binaryFormatter.Serialize( fileStream, systemObject );

systemObject = new object();
systemObject = "Hello this is testing2";
binaryFormatter.Serialize( fileStream, systemObject );
}
// catch(Exception ex)
// {
// avoided for getting noticed what happened;
// }
finally
{
if ( fileStream != null )
{
fileStream.Close();
fileStream = null;
}
binaryFormatter = null;
systemObject = null;
}
}
}

please help in this matter as i am stucking in the problem from more than 3 days.

this thing is happening OK :
1. if i call this method directly on another method.
2. if i call this method in a console application .
3. if i call this method on a thread in a console application.

any help would be highly appreciated.

thanks

vishal sharma