The depreciated global property formentry.infopath_archive_dir is added automatically. Delete it, and it will come back automatically after restarting.
This then causes the following warning in the log file...
This happens in OpenMRS Version: 1.6.0 Build 12644 with FormEntry 4.4.1 and 4.4.2.
See similar Ticket
TRAC-1039 where the warnings were being added for no reason.