Excel Automation with Security Problems
 

I try to automate Excel in C++ with the following statement
--------------------------
_Application ptrExcelApp
Workbooks ptrWorkbooks
_Workbook ptrWorkbook

ptrExcelApp.CreateDispatch("Excel.Application")
if ( ptrExcelApp.m_lpDispatch == NULL
AfxMessageBox("Excel not installed")

// Use Exce
ptrWorkbooks = ptrExcelApp.GetWorkbooks()
...
ptrExcelApp.Quit()
---------------------

Everything works fine but when I change the default security setting with DCOMCNFG it doesn't work anymore
I change the default access permission and grant the DOMAIN-ADMINS the access right. After that I can't start Excel anymore. Everything works fine again when I remove the right
By the way, the Microsoft CRM Business Solution doesn't work with this security change either. I get an access denied when I try to load the main site via Internet Explorer
Any suggestion

Thanks in advanc
Harr