delphi and printing

[St�phan S�mirat]

neither the following command  doesn't seem to work 
Browser.ExecWB(OLECMDID_PRINT, OLECMDEXECOPT_DONTPROMPTUSER, vaIn);
i have the following error message :
exception EOleException
and (in french !)
"Tentative de r�vocation d'une cible de d�p�t aui n'a pas �t� enregistr�e"

Well, have i missed something ?
I've recently installed Mozilla and the control (1.4), i run under delphi 6 and win XP.

Thanks for any help