To load a library or tool from the PIDE then it has to be 'packaged' in a way that Processing can use  The rules for pakaging are now strictly enforced with 2.0b8 and only those correctly pakaged will be made available via the PDE.

It is upto the library developers to update their libraries and package them correctly.

In this case you will have to do a manual installation.

PS I have moved this topic to the Contributed Libraries forum.