Re: OpenBSD 3.9 -> 4.3: pfctl Cannot allocate memory

[Bryan Vyhmeister]

As you can read from the first lines of the upgrade guides, "Upgrades  
are only supported from one release to the release immediately  
following it. Do not skip releases." It is very likely that this is  
the cause of your problems.

http://www.openbsd.org/faq/upgrade43.html
Bryan