OleFunction does not work with Excel 2003

[galgani]

Hello,
I have design a function in C++ that export data in Excel2K; the
problem is when I uploaded my Excel 2000 to Excel 2003.
The following code works fine on Excel 2000:

if (rExcelIsRunning == false)
{
cExcelApplication = Variant::CreateObject("Excel.Application");
cExcelApplication.OlePropertySet("ScreenUpdating",false);
cExcelApplication.OlePropertySet("EnableEvents",false);
cExcelApplication.OlePropertySet("DisplayAlerts",false);
}
else {....}

cExcelWorkbooks = cExcelApplication.OlePropertyGet("Workbooks");
cExcelWorkbook = cExcelWorkbooks.OleFunction("Open",
rDestinationFile.c_str());
------------> RAISE EXCEPTION: class EOleSysError with message
'Eccezione' <----------

What does it change between Excel 2000 and Excel 2003 about Ole
Automation.

Thank's for the help.

Claudio