I have just one question, how can I in a nt-network environment with
different users make sure that my OleAutomation server is run only once. The
problem is that two users with different username runs the comclient the
oleautomation server is run two times and so on.

Only if I login on bot client computers with the same username I can get it
to work.

Any good ideas?

I granted total access to everybody in dcomcnfg. On one client I'm using the
administrator account and on the other just a normal user account. I've also
tried with another username which have administrator rights but it's the
same everytime, the server is launched twice :(

Take care
  B.

P.S. Thnx to Binh Ly for his very good explanation of callbacks.