Date errors in admin and mobile templates - repost

There is an error message displayed in the admin area of the website after the change to winter time a few weeks back. It didn't bother me much first. But I recently discovered that the mobile version of my page is unusable due to this error popping up all over the place. The line identifier is different in the error message and seems to apply to alot of different code lines. Anyone know how to fix it? I imagine there is a quick fix to this.