The main symptom is the plesk update failing with an error message like this:
ERROR: The required version '3.10.1' was not found on the server.
This could happen because of configuration error at the download site
The MD5 checksum of the /var/cache/parallels_installer/parallels_installer_CentOS_5_x86_64 file does not match the value specified in the configuration file.
This is caused by a new Plesk autoinstaller capability for self-upgrade prior to upgrade of the Plesk panel and the lack of correct files in the mirroring system. We are in contact with Parallels to fix this problem.
In the meantime you can workaround the problem by upgrading the panel via SSH:
/usr/local/psa/admin/bin/autoinstaller --source-type network --source autoinstall.plesk.com --select-product-id plesk --select-release-latest --upgrade-installed-components
Update(s):
Date: 2011-10-20 10:10:29 UTC The issue is fixed.
The reason is that some files weren't detected as \"changed\" by rsync.