You can upgrade from 5.0.x to 5.1.30 with cPanel scripts
/scripts/perlinstaller –force Bundle::DBD::mysql
to reset the new install
ERROR! MySQL manager or server PID file could not be found!
This error is caused by the my.cnf file that comes from mysql4 or an earlier version. To correct the error, enter the following commands:
mv my.cnf my.cnf.old