Terror Urban Legends: The e-mail from an old roommate had the whiff of too many hoaxes, from its dubious opening -- "my friend's friend was dating this guy from Afghanistan . . . " -- to the overheated warning at the end: Everyone avoid the malls on Halloween! Mary Beth Goodman didn't believe it. But in the days since Sept. 11, who knew what to think anymore? their name, address, credit card number and other personal information and to send the form on to its digitized charitable destination. It's easy. It's also a scam. The warning, it turns out, has no basis in reality, according to law enforcement officials. Neither does the one about hundreds of trucks reported stolen, supposedly by terrorists planning another massive assault. Nor, say other authorities, are many other rumors that have spread since the terrorist attacks, like the one about Osama bin Laden profiting from worldwide soft drink sales, or Peter Jennings accusing President Bush of cowardice on the air.