1. Tried update 1.5 Pre with MySQL 5.1. No luck - just upgraded to 1.5 final, no touch to MySQL.
2. Then uninstalled MySQL 5.1 and tried to upgrade - also nothing.
3. Then uninstalled MySQL 5.1 and MP (not full, just application) and made upgrade (exactly - upgrade, MP with left config and user files is making upgrade) - no luck.
4. Then Uninstalled MySQL 5.1. uninstalled fully MP programs, rebooted and made fresh install - then all gone well.
All was done on non-production machine, so not good to try on HTPC.
May be there could be easier way to make some upgrade script for upgrade MySQL 5.6 only? For those that want to make upgrade for current installations.