Importing jenkins from a zip archive not working in older versions of Bamboo

When yo tried to perform the import using an archive, Bamboo throws an "unknown server error" with nothing shown in the logs.

This is already fixed in Bamboo 5.2.1 and as such, you will need to upgrade your instance or alternatively upgrade the bamboo-jenkins plugin as thus:

1. Download the attached version of the plugin which is 5.1
2. Replace the current version in the atlassian-bamboo\WEB-INF\classes\atlassian-bundled-plugins.zip file
3. Delete the current HOME/bundled-plugins directory
4. Restart Bamboo