[newbie] Simple token in textarea not being processed

hi folks,

firstly apologies for what is probably a dumb question. However, this has driven me to the point of madness.

Objective: in a custom content type, print the site name (or user name) using the token [site:name]

Setup: Drupal 7.10 + Token Insert 7.x-2.0 + Token Filter 7.x-1.1

Description:
I have created a basic new content type. In the Body field I insert [site:name]. When I create an instance of that content, what is printed to screen is literally [site:name] and not the name of the site.

I have checked permissions, cleared cache, ensured the token is available using Token Insert configuration.

I know this is really basic, however at this stage I can't see the "wood for the trees".

any advice, etc. is gratefully appreciated.
rgds Dave