Fatal error: session_start() [<a href='function.session-start'>function.session-start</a>]: Failed to initialize storage module: user (path: /tmp) in /home/efirst/public_html/shop/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php on line 125
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Is the /tmp partition on your server writable by the web server? Next, what is being used as the session storage? Open app/etc/local.xml and locate the following line:
<session_save><![CDATA[.....]]></session_save>
It could be set to any of the following: db, memcache, files. Make sure it is set to “files”.
Also check if there is a custom <session_save_path> entry present.