Watching last Friday's performance of Pitching Penguins, a satire of the inner office politics of a Chicago public relations firm, one gets the notion that somewhere along the line the plot got in the way of the writing. The premise is a solid one; a former number one p.r. agency is fighting its way back to the top trying to place inane new products including delectable penguin wings, a giant cheese ball made of Swiss and Cheddar (SWEDDER) and eating utensils that voice Don Rickles insults. Just that on paper is enough to make one laugh. So the problem with the Flaxen Theatre's new comedy by David Brimm and Michael Rosenbaum, who themselves spent decades working at Chicago's top agencies, isn't the premise, it is the execution.