Vista - Permissions and security to access files and folders

I've recently implemented licensing using Macrovision/Acresso flexnet
publisher. Everything works well in XP but that is not the case in Vista. I
created a DLL that calls the necessary license API's. If I write an
application that checks for the license count, log in as an administrator and
run my application the license call works fine. As part of our install there
is also a COM+ server running. The COM+ server has to validate a license in
order to perform some functionality but when the COM plus server calls the
API, the API returns no licenses.

The COM+ server is running as userX, which is an account that is created
when our software is installed. userX is a member of the Administrators
group. So if I run comexp.msc and change the COM+ server to run as the
logged in user, the COM+ server is able to get a valid license.

This seems like an issue with permissions and security, although I don't
know why the userX who is also an administrator should have an access issue.

How do I track this down? I've turned on all of the audit policies I could
find and when the license check fails I don't even see a warning that
something was denied. I've tried running sysinternals process viewer to see
what the difference is between my working application and the COM+ server but
the access that is attempted by the COM+ server doesn't look at all like the
access my application performs.

Any help would be appreciated
James