VB6 to .Net Interop issue

Yes, I have registered the TLB from local system drive and it worked fine.
Here is a part of the COM interface. All namespaces and classes not mentioned here.
In the below code, RecordUserService is exposed to VB6 through the interface.


// COM Interface specification
[Guid("D6F88E95-8A27-4ae6-B6DE-0542A0FC7039")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface RecordUser
{
[DispId=1]
string callService(int userId);

[DispId=2]
string DBConfigPath;
}

[Guid("13FE32AD-4BF8-495f-AB4D-6C61BD463EA4")]
[ClassInterface(ClassInterfaceType.None)]
public class RecordUserService: RecordUser
{
public RecordUserService() {}
public string callService(int userId)
{
// Create WCF service client and invoke webservice method.
// Return "Success" if service is executed fine and "Error" in case of errors.
}
public string DBConfigPath
{
get
{
// Get private variable for db connection
}
set
{
// Set private variable for db connection
}
}

// Private methods internal to the middleware interface
private void initRequest()
{
// Initialize Web service request
}
private void sendRequest()
{
// Invoke web method and get back the response
}
}