updating

You could try a manual update: http://codex.ww.wp.xz.cn/Updating_WordPress#Manual_Update

The automatic update could be failing due to the server running out of memory or other limitations due to a misconfiguration on the server.

You may be able to increase memory the available to PHP, otherwise the only other option I can think of is to contact your hosting company in case it is a know issue on their servers for which they have a solution.