Problem with Project's COM Interface

[Peter Katsoulas]

We have an application written in C++ under VS 2008 using CLR. It has a
feature which uses a COM interface to pass data to MS Project 2007
Professional. If Project 2007 SP2 is installed and only if SP2 is installed,
the COM error -2147219988 is produced.

The Microsoft expalnation is:

Couldn't Backup Destination SysDataUpgrade Procedure...TERMINATED"This error
occurs when upgrading through the install in the InstallAssist.Log orif you
are running the InstallAssist from the exe.

This COM error comes from the following call to the MS Project interface. The
instance ( SPRMPDFile::GetMSProjectApplication()) of MS Project appears
correct. I agree that this error makes no sense.

SPRMPDFile::GetMSProjectApplication()->FileOpen
(
(_bstr_t) m_strXMLPathName,
nullVariant, // not readOnly
(long)MSProject:jDoNotMerge, // merge flag
nullVariant, // taskInformation
nullVariant, // table
nullVariant, // sheet
nullVariant, // noAuto
nullVariant, // UserID
nullVariant, // DatabasePassWord
_T("MSProject.XML"), // formatID for XML file
nullVariant, // map
MSProject:jPoolReadOnly // PjPoolOpen
);

Does anyone have any ideas? Is this an MS Project 2007 SP2 problem?