Though I haven't experienced this error, have you Googled to see if others have?
The first thing I noticed was that you're running an old version of PHP (even the subversion, .3, is a whole step behind the latest) and you might consider upgrading, especially if this turns out to be a bug or something along those lines.
EDIT: Also, moved thread to the 'General Help' forum instead of the 'PHP5' forum which, incidentally, is dedicated to problems occured while using PHP version 5.