On one of my servers the upgrade to plesk 9.2.1 failed. It was because in mysql 5.1 they changed one of the queries:
Trying to check psa database... Trying to find psa database... version is 0901
ERROR while trying to execute SQL query, the query was: DELETE FROM mysql.user WHERE user = ''; FLUSH PRIVILEGES;
Check the error reason(see log file: /tmp/psa_9.2.1_fc8.build92090422.13_upgrade.090429.08.45.log), fix and try again
Aborting...
I got around the issue and its working well. However Parallels you need to update your query to be current with mysql.
Trying to check psa database... Trying to find psa database... version is 0901
ERROR while trying to execute SQL query, the query was: DELETE FROM mysql.user WHERE user = ''; FLUSH PRIVILEGES;
Check the error reason(see log file: /tmp/psa_9.2.1_fc8.build92090422.13_upgrade.090429.08.45.log), fix and try again
Aborting...
I got around the issue and its working well. However Parallels you need to update your query to be current with mysql.