heaps of threads on the "other" sections.
Its all the data that does not fit into the sections listed there, audio, movies, photos, apps, backups.
So basically all your documents, program files, downloaded files etc.
Try DiskInventory X to find the files which are stealing your space. I Use this program all the time
Whats damaged? The program or your Hard drive?
Open Disk Utility, select your hard drive and click verify disk.