The Rev A boards have an updated circuit and firmware from the 0.3.4 branch. Use the parallax.py file from the library folder in the 0.3.4 branch. Any version newer (higher) than 0.3.3 will work with the Rev A boards.
Also, if you are using a Rev A4 board, make sure to use the cyberbot-0.3.2 release.
The Rev A boards have an updated circuit and firmware from the 0.3.4 branch. Use the parallax.py file from the library folder in the 0.3.4 branch. Any version newer (higher) than 0.3.3 will work with the Rev A boards.
Also, if you are using a Rev A4 board, make sure to use the cyberbot-0.3.2 release.