Matt Liston’s Chasing October is less a documentary than a phantasmagoria about the fever dream that was the Cubs’ 2003 season — you remember, the one that ended with Steve Bartman’s muff, Alex Gonzalez’s error, and the Florida Marlins advancing to beat the New York Yankees in the World Series. No movie that opens with the ghost of Harry Caray telling the filmmaker the Cubs will make the World Series if only everyone will “Just Believe” can be taken as the unvarnished truth. But only in an obscure corner of the movie’s Web site does Liston admit that he actually considers the film a “doc-u-comedy, blending real documentary footage with scripted scenes.” This calls into question the entire subplot involving his relationship with his supposed girlfriend, Faline England, who turns out to be, yes, an actress. At that point, what’s to believe? Intense Cubs fans might get a few self-flagellating laughs when they see it at the Music Box, but most others will be sorry to find this film fallen into the nether region between fact and fiction. If Liston was going to make things up, he should have gone ahead and scored the first interview with Bartman — even if it would have been scripted with an actor in the role.