According to this new post on DynamicWebPges.de and a message from Derick Rethans on the php.internals mailing list, there's an issue with PHP 4.4.5 where sessions are causing segfaults when register_globals is set to "On".
As per Derick:
Because of this I'd like to release a 4.4.6 soon with this fixes. As there is also an upgrade to pcre 7.0 we'd need at least one RC, which I plan to release on Thursday.
Users of the PHP 4.4.x series should keep watch for this new update to correct the issue quickly.