Date errors in admin and mobile templates

After the change to winter time a few weeks back I get this error message on the admin page which didn't bother me much. 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.