Encode exceptions "&"

Hi,
I added the following to the encode exceptions in Sef Advance 2008 2.21 (Joomla 1.5.15) "&=>and" in order to replace all "&" with "and".

Unfortunately this has caused ANY link eg "grand paradise beach resort" to give a 404 error and the word has "and" in it......wierd!

As soon as I remove the encode exception the urls work perfectly.

Any idea as to why this is happening?

Many thanks,

Pete

Yes. It's explained here: www.sakic.net/support/faq/sef_advance/#20