Arduino Uno comptibility with LCD03

I was measuring some timings for my latest project, using an Arduino Uno, when I hit a problem. The whole sketch stopped working when I added the code for the LCD03 liquid crystal display. Eventually I uploaded the LCD03 example sketch "hello world", but that did not work either. The Uno still appears to be working with sketches that do not use the LCD03, but stops working every time the LCD03 is included.

Eventually I discovered that the sketch did work when I uploaded it to a Freeduino (Diecimila equivalent, fitted with a ATMEGA328P in place of the original 168).

This surprises me since both the Uno and the Freeduino use the ATMEGA 328P, and I believe they are pin compatible. Can anyone suggest where to look for the cause of this problem, please?

I believe that the version of LCD03 I am using is the latest. It states that it supports Arduino 1.0.0 and newer, and is dated 2013.

Many thanks.