Even Chicago, one of the most beautiful cities in the world, is made to look grubby in this wafer- thin, poorly mounted romantic comedy about a fellow who meets his dream girl on the Windy City El Train but fails to get her name or number, and then must engage in a public campaign to find her. (While some exteriors were shot in Illinois, it should be noted, most of the picture was filmed in Canada, and the locations don’t always mesh.) The premise is just a dumb variant of the increasingly prevalent theme of fated love that found perhaps its best-known example in “An Affair ro Remember,” and was most recently featured in “Serendipity.” Still, in spite of its narrative familiarity, “On the Line” might have been reasonably amusing fluff if it weren’t so abominably written, directed, and acted. As it is, the picture is wretched from first stop to last.

It also should doom any screen career for Lance Bass, the ‘N Sync pretty boy who stars as Kevin, an amiable ad agency clerk who becomes a celebrity by searching for Abbey (Emmanuelle Chriqui), the vivacious chick he conversed with on their way to the Loop one morning. Bass has a clean-cut eagerness which obviously appeals to prepubescent girls, as the band’s stage success demonstrates, but as an actor he proves entirely charisma-free, with a distinctly limited range of expression stretching from a broad smile, through a pallid smirk, to a look of doe-eyed innocence. Even at that, though, he’s lot more tolerable than his fellow band member Joey Fatone, who plays the crudest of the Three Stooges who are Kevin’s best buds (the others are GQ, sort of a scummier version of Chris Kattan, and smoothie James Bulliard, the obligatory preppy type) and are instrumental in fouling up the hunt for his beloved. Fatone comes across as a complete lout, a low-rent Jim Belushi whom any sane person would cross the street to avoid. (To be far, he’s still better than a couple of other ‘N Sync guys who show up in an ersatz “Behind the Scenes” epilogue tagged on before the closing credits; fans might find the self-referential patter amusing, but it’s so lamely scripted and flatly played that it’s painful.) Chriqui, to tell the truth, is no great shakes, either. She looks agreeable enough, but there are definitely no sparks in her meeting with Bass. That leaves the feeble plot even more rudderless.

Some old pros are trapped in the wreckage of this amateur night, too. Dave Foley struts and puffs his way through the role of Kevin’s pompous boss in a fashion that makes one long for the more laid-back approach of his television work, and Jerry Stiller, looking worn and haggard, stumbles about as the lovable office grouch. Tamala Jones does a stock hardbitten turn as Jackie, our hero’s account colleague, who at first steals his ideas but later shows a softer competitive side. Al Green is dragged in for a couple of musical numbers, which is fine but pointless.

It’s hard to get too worked up about a flick like “On the Line.” It’s unremittingly awful, but given the actors and crew involved, it probably never had a chance, and should be allowed to sink into well-deserved obscurity without much fuss. After all, writers Eric Aronson and Paul Stanton and director Eric Bross had so little sense of reality that they actually included a scene in which Kevin and Jackie make a presentation to Reebok reps–the company is mentioned so often it really deserves above-the-title billing–that goes over so badly that the sound of crickets is added on the soundtrack to emphasize the deadness that follows it; surely if the makers had the slightest sense, they might have realized that their picture would deserve a similarly ignoble fate. As for moviegoers unlucky enough to stumble into auditoriums where this rickety contrivance is running, the best advice is to disembark before it starts up.