We don't know how this error occurs. It is not specific to WorklogPRO and can happen to any add-on as discussed here. Solving this error requires you to run DDL statements in your database. What you need to do is: 

1. Remove WorklogPRO add-on
2. Stopped Jira
3. Export data from all tables with AO_7B9828 prefix
4. Drop all of the tables with AO_7B9828 prefix
5. Started JIRA
6. Install WorklogPRO add-on
7. Re-import the data exported in step 3