Error with EmailReporting in MantisBT 2.27.1

[juanesteba20]

I recently migrated my site to the latest version of Mantis, and everything is fine with that. The problem arose when I tried to install the "EmailReporting" plugin. With version 0.10.1, it wouldn't let me access the "Manage Mailboxes" section, so I decided to install the development version "0.11.0 DEV." With that version, it allows installation and I can access all sections correctly. But when trying to add, copy, edit, or test a mailbox, I get the following error:

[SL-Gundam]

You might still need to run the upgrade script for MantisBT.
MantisBT made a change with categories. This causes that all categories are disabled if the upgrade script is not run.
Please check to see whether you have a existing and enabled global category in MantisBT.

ps. sorry for the late reply. I was on vacation.