Hi @JGWZG,
To install the Palladian nodes, you’ll need to add the following update site: http://download.nodepit.com/palladian/4.1.
The process is described here: Palladian nodes gone after update to knime 4.0
As for your your Loop End problem, the error means that one (or both) of your tables is changing throughout the loop, perhaps the name/number of columns is changing during each iteration. It is possible to configure the Loop End node to allow changing table specifications, but you’ll need to investigate what’s going on.