The initial error was probably reported to root mail and/or the console, and reviewed using errpt. You look at "errpt -a xxxxxxx' the error, to see a detailed explanation of it before starting, giving you the initial info.
It appears the filesystem had a hard error (The file header is corrupted). The cause of which is not clear from the info provided. In any case, you typcially have to unmount the filesystem to get write access to fix it. Before you can unmount it you would check to see if anything is using it with "fuser /filesystemname". If anything (pid) is returned you must first stop or kill those processes to free the filesystem, so it can be unmounted. FIRST, you must make sure it is safe to stop/kill those processes based upon your application. Once they are stopped, then "umount /filesystemname" and run "fsck /filesystemname" to repair it. Carefully record what fsck reports it does to fix the filesystem, as it may delete items you need to put back. Once fixed, then you do "mount /filesystemname", put back anything you need to, and you are finished.