A new release of the filemgmt plugin is now available that addresses a potential security issue reported to me by Mark Evans. Additionally, this version resolves a number of issues with the display of sub-categories and now better handles displaying sub-categories and the number of files they contain.
There are no database changes so all that should be required is to replace the changed files or complete directories. Existing sites running version 1.5.2 or earlier need to run the plugun upgrade - from the plugin editor listing. This will update your installed version to reflect version 1.5.3.