1) PHP needs to have enough memory, make sure you have it before running the scripts.

2)The running updateclasstranslations.php script more than one time will corrupt the names of classes and class attributes

Coppied comment from here: http://ez.no/doc/ez_publish/upgrading/upgrading_to_3_9/from_3_8_x_to_3_9_0

Steps to reproduce

Run twice the updateclasstranslations.php script and you'll see the second problem.