Prague Czech English Dependency Treebank 2.0 (PCEDT) is a parallel, bilingual corpus. The English Part is based on Penn Treebank 3 and therefore to use PCEDT, you need a license for Treebank 3.
The dependency annotation of the English data, as well as all the Czech data is licensed under the terms of CC-BY-NC-SA 3.0.
By accepting this license and downloading the data you declare you have a valid license for Treebank 3.