That's what it says when I try to install the W8 Consumer Preview from the disk I burned. I've burned two separate disks with the same result. I opened the "bootmgr" file using notepad and there actually is some text saying "bootmgr corrupt". What now?
The bootmgr file will have various messages in it, but that doesn't mean that the file is corrupt. It usually doesn't do much good to open the bootmgr file with notepad. The suggestion above about verifying the checksum of the download.