Error Code: 1071. Specified key was too long

Error:

I'm trying to move my Back-End database from HSQLDB to MySQL. While executing the create-backend-mysql.sql in my schema, execution stopped abnormally saying the below error.

CREATE INDEX IDX_AU_TASKLIST_au_hiActivityDescription ON AU_TASKLIST (au_hiActivityDescription)
Error Code: 1071. Specified key was too long; max key length is 767 bytes
0.000 sec

Cause:

You are using an incompatible version of MySQL.

Solution:

Try using MySQL v5.5