Upgrade from 4.4.19 to 4.4.2 DB error
Version 4.4.19 is the latest LTS version of CiviCRM.  The next LTS version will be 4.4.20.  V4.4.2 is an old version that came after 4.4.1 and before 4.4.3.

Not surprising CiviCRM is not happy with you trying to downgrade your site.

If you add a link to the question that referred to waitlist error I can have looked at that to see what versions it refers to.  It could be talking about the 4.6.X series.