Concurrent access to COM interface


I want to use the COM Interface as part of a server process (svn post-commit hook). There might be situations where more than one user triggers generating a PDF file more or less at the same time.
If I look at the examples, the queue is initialized, the document is sent to the printer and then the process/script waits for the next job and perhaps manipulates the job settings (e.g. fills in meta data fields).

How do I know that the next job is the job that prints the file I sent to the printer in the same process and not the file of another job?

Is concurrent access to the COM object allowed at all? I think I read somewhere that PDFCreatorQueue.Initialize() will fail if PDFCreator is already running.

Will ReleaseCom() terminate the PDFCreator even if it is still used by another process?

Thanks for your support!