HI,
I have tried the same, but got a bit further, you have to cut & paste the details out of the includes/local/configure.php file and out them into your includes/languages/english.php file. There is also one for the admin section.
I have the contribution installed, but I only get a pull-down box for the attribute on the products_info.php page... so am getting a bit stuck/frustrated as need text input from customer!
Any other ideas would be greatly appreciated!