Home link in non-default language recieves a HTTP Forbidden 403 error

Hi,

I have Drupal 6.1 with English and Japanese installed.

English is the default language.

Switching between languages is fine on the frontpage with the following links on the locale switcher:

English: http://localhost/drupal-6.1/en/node
Japanese: http://localhost/drupal-6.1/ja/node

Navigation is Japanese is fine too.
For example: http://localhost/drupal-6.1/ja/book

HOWEVER!!! When I follow the 'Home' link in Japanese mode it produces this link:

http://localhost/drupal-6.1/ja

That link leads nowhere and gives a 'The website declined to show this webpage' Http 403 error.

However in English the link:

http://localhost/drupal-6.1/en

works perfectly and takes me to the frontpage in English.

The link to Home for Japanese that works appears to be:

http://localhost/drupal-6.1/ja/node

Whereas:
http://localhost/drupal-6.1/ja

just doesn't work.

Is this a link problem or is there an option or code tweak that gives permission to http://localhost/drupal-6.1/ja?
It seems like a mod-rewrite kind of thing ut I am new to Drupal and not sure how it all works together yet.

Any help or suggestions would be great as it really messes up implementing a multilanguage site is the Home url keeps failing.

Thanks.