The Adobe PDF Library and Adobe Normalizer may be run in the same thread. But the two products must be initiated and terminated together, and they must be terminated in the reverse order that they are initiated. If Adobe PDF Library is initiated first followed by Normalizer, Normalizer must terminate first.
Also, both products must be initiated and running before either can be used. If you plan to run both APDFL and Normalizer together, you can’t start APDFL, run an APDFL function, and then start Normalizer. Likewise, you can’t terminate APDFL, process a few PDF documents with Normalizer, and then end Normalizer.