I got the error message after follow steps at
http://wiki.i-mscp.net/doku.php?id=start:upgrade:debian
/usr/local/src# tar xvzf imscp-1.1.0-rc4.6.tar.gz
tar (child): imscp-1.1.0-rc4.6.tar.gz: Cannot open: No such file or directory
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now