e2fsck not detecting corrupt file?

[Alex Bligh]

--On 18 November 2005 17:03 +0100 Jochen Tuchbreiter <jt at domainfactory.de> 
wrote:

> $ chmod a+x /mnt/path/usage_200306.html
> chmod: changing permissions of `/mnt/path/usage_200306.html': Operation
> not permitted
>
> The fs is NOT mounted readonly, I can move around / change other files on
> the partition.

Is it marked as immutable (somehow)? As root, try:
 chattr -i <file>

Alex