>When the com server report a error, i execute COMERROR with the message, but ALWAYS in the client i get the error Ole IDISPATCH ?:? or something like this...

What you're supposed to do is trap the COM error and get more info after that. So if its a 1429 error (or something like that) you can then call aError() to get the real error message. See the docs for which elements you want (if I remember right, 3 and 4).