Unix: owner of directory cannot Write to directory?

Hi All,

I am the owner of a directory in Unix (really Mac OS X, but should be the same thing).  And I get a "Permission Denied" error when I try to write to that directory.

I believe I am the owner of the directory because it gives me the following output when i do ls -l

dr-xr-xr-x  158 jusTellme staff  16384 Apr 29 21:38 Videos

And when I do whoami, I get:

jusTellme

So, when I try to write a file to that directory, it gives me a an access denied error.

But when I do   chmod 777 Videos, so that I can write to that directory, I get:

chmod: Movies - Unwatched/: Permission denied


So, I believe I am the owner of the directory, but I cannot write to the directory.  I am trying to change the permissions but no luck.  Is there another way to change the permissions or a tool/script that I can use to change them so that I can write to this directory again?

Please help...