The problem is that you don’t have page (probably deleted) with id=78 that are in the database.
You need:
1. deactivate plugin
2. delete row in database in table wp_options. Parameter name is ‘jobman_options’
SQL query is:
delete from wp_options where option_name = ‘jobman_options’
3. activate plugin (it creates new page for job list with new id)
