Ok, so I’ve just uploaded a zipped update site of the Palladian nodes. It’s available here:
http://download.nodepit.com/palladian/4.0.zip (it’s the same version as available on the corresponding update site)
Due to lack of time, I didn’t double check, if the installation works fine with this. Especially, there’s one potential obstacle which might still cause trouble: Palladian has (currently) a dependency to the KNIME Textprocessing nodes. I.e. when installing Palladian, and the Textprocessing nodes are not installed, KNIME will need to install them as well (they are not included in the zip file, instead they’re available on the KNIME official update site. KNIME resp. Eclipse resp. P2 should be able to figure this out automatically – that’s what I hope 
).
Could you please try whether you can install from this file? (instead of setting a URL, just specify the path to the zip file and then run the installation as normal).
Does this work?
Best,
Philipp