Should this be in the FAQ page?
Having struggled with this problem for 2 days, I was very surprised to find that there is a simple solution.
The answer appears to be to add this line to the .htaccess file in the root directory of the specific Joomla installation:
"Here's what works for me. I'm using Joomla 1.5.3, SEF: on, Apache mod_rewrite; on. Just add this line to your .htaccess."
The author of this fix is to be found here: http://forum.joomla.org/viewtopic.php?p=1289015&sid=ff0da8dfe820f605d8dd5faf09222fb0#p1289015
Just don't forget to comment out this line after changing one's site configuration ...
hope that this helps others. John K