@ dxw00d - You've hit it on the head. Doing a Google search for "Arduino !!!" turns up these threads...
http://arduino.cc/forum/index.php/topic,49591.0.html
http://arduino.cc/forum/index.php/topic,46966.0.html
and for the explanation -
http://code.google.com/p/arduino/issues/detail?id=392
I thought I would be the only silly one to come unstuck by this, but it seems to have trapped a few.
Thanks all for you help - beware the evil !!!