The Erk meeting probably is a parody of Est, a series of self-improvement workshops popular in the 1970s through the early '80s. Critics of Est alleged that it was a cult that practiced mind control and encouraged authoritarianism.
During the ERK meeting with Ellsworth, Mork raises his hand and mistakenly says, "Point of Ellsworth, order!" (instead of "Point of order, Ellsworth!") The phrase "point of order" is used in parliamentary proceedings when a member asks the leader whether a rule has been broken. In American history, the phrase is associated with Communist-hunter Senator Joseph McCarthy, who frequently used it during what are known as the Army-McCarthy Hearings (1954-1955). (See the documentary film Point of Order! (1964).) Notwithstanding Mork's unlikely knowledge of the phrase (he certainly doesn't know how to use it), the writers of the show use this as a way of of hinting that Ellsworth might be a tiny bit like McCarthy, who in the aftermath of the Hearings has generally been considered a villain. A further part of the joke is that David Letterman is a Democrat, and thus would have been considered a Communist by McCarthy.
Paul Williams is a short man known for, among other things, the role of Little Enos Burdette in the action-comedy Smokey and the Bandit (1977).