Hi,

I'm building a Web Service in .Net and I get the following exception "System.InvalidException. QueryInterface Error" when I try to call a COM+ component in a ASP.Net page. I'm using C# to call the component which was developed in C++. The component works fine when I call it in a ASP page or a VB6 app. This is my code:

[WebMethod]
public string Login(string user, string passw)
{
   iSicresAsp.Session Sess = new iSicresAsp.SessionClass();
   Sess.Login(user, passw);
   .....

I've added a reference to the dll in my project.

Thanks in advance.

I had the same problem and finally got the solution:
Give Read permission to ASPNET user on the COM used. It's necesary to namely assign this permission: assing Full Control to Everyone is not enough (?).
I hope this helps.
Regards.