Mozilla language change problems

After having installed successfully Knoppix (3.3 19-11) on my hard disk I wanted to change the interface language of mozilla (version 1.5 that comes pre-installed) from English to Spanish. Something I have done many times under M$ Windows 2000 with no problems and also under Red Hat 9.

Firstly I tried as the knoppix user and was told I do not have permission to modify the directory. So I repeated the procedure as root and it appeared to work ok.

The problem is that if I try to run mozilla as knoppix I get an error console (mozilla.bin) from mozilla with a lot of messages (all in red), the first few lines being:

<window id="main-window"
^
<menuitem id ="edit_prefill"
....^

etc.

There are a few pages, but since mozilla will not let me copy them it would take too long to type them in by hand.

Now, if I run mozilla as root, it works fine, so I thought it must be a question of permissions, however, I have even changed the mozilla directories:

chmod -R 777 /var/lib/mozilla/*

And it makes no difference...

Any suggestions?

Many thanks.

Tim