Ok,
Have consistently got it working now having done the file repleacements mentioned earlier in the thread on both Arduino 003 & Arduino 004. There is a bit of a knack to upload to the board (its a USB one) though.....
To get it to work I hold down the reset button, click the Upload button and wait a couple of seconds. Then I release the button and a second or so later both the TX and RX Leds on the board light up and both start flashing. The upload then occurs.
Releasing the Reset button before clicking on Upload results in the error, 'Programmer is not responding', and the previously uploaded program continues running on the board prior to either green LED flashing. (speculation: which suggests to me that the upload is taking too long to commence and some form of timeout is occurring?)
plaidTortoise