Am trying to upgrade joomla site and am receiving a message just like this:

Warning: fopen(/home/preache2/public_html/testpki//home/preache2/public_html/tmp/jupgrader.xml) [function.fopen]: failed to open stream: No such file or directory in /home/preache2/public_html/testpki/administrator/components/com_jupdateman/libraries/joomla/filesystem/stream.php on line 166

Download Failed: Local output opening failed: fopen(/home/preache2/public_html/testpki//home/preache2/public_html/tmp/jupgrader.xml) [function.fopen]: failed to open stream: No such file or directory(43)

Any idea on how I can sort this out?