Its strange that nothing is happening - firstly are you copying the file away from the FFXI directory prior to editing? Even in admin mode Changetex may have trouble altering files that require admin access (though it'll quite happily report it was successful)
Best thing to do is copy the files elsewhere prior to making the changes, then move them and overwrite ROM/0/14.dat - set the in game option to 1 for this to work
If you're still having issues and are able upload your dds files and I'll see if I can get them to work my end
OMG >< spent so many hours trying to save in different formats turns out its this: http://imgur.com/m7OiAmf ....
Had to turn off read only on the dat file properties.
Thanks for your help, when you mentioned admin I got to see those settings....