>It is DLL. As I said, I tried to run it from another computer in the local area network, and it workes. Our network based completely on the TCP/IP protocol. I used exactly the same way of object instantiation. Why it does not work through Internet? What the difference?
>

Huh? You got a dll to run through DCOM without using MTS? Unless you are very familiar with DCOM and the other methods of assigning a surrogate to an in-proc dll, I would venture to say that you hadn't done what you think. A dll is in-process which, by definition, has to run in the same memory space as the process that created it. If it lives on another machine, this is impossible unless the dll is configured to always run in a surrogate process (like MTS).