shut down of the server after invoking com component

Hi,
I try to call an excel file with VB macro through the integration server.
To do that :
I first create an instance with createObject with guid Excel.Application
After I invoke Workbooks with get accessType
And finaly I invoke open with method accessType.
At this moment the server shutdown without any information.
I’m currently working with 4.6 release and I’m pratically sure that it was working with previous releases.
Thanks for your help.
Thierry.