I am using an external USB hard drive for a long time in Ubuntu 10.04, both at work and at home. Now I've installed 12.04 at home. Today I used the USB drive for the first time. I can read the disk but can't change the permissions of a file I wanted.

Output of "mount"

/dev/sdb1 on /media/FREECOM HDD type vfat   
(rw,nosuid,nodev,uid=1000,gid=1000,shortname=mixed,dmask=0077,
utf8=1,showexec,flush,uhelper=udisks)

What I try

sudo chmod u+w bsst-hdf_to_bsst-h5

and what I get

-rw-r--r-- 1 paco paco 2956 dic 19 10:27 bsst-hdf_to_bsst-h5

Any idea would be appreciated. Thanks in advance