(Portland, OR)  --  No injuries are being reported after a fire broke out in the basement of a historic bar in Northwest Portland.  Fire officials say the blaze was reported around 7:30 last night at Slabtown, a famous dive bar and music venue on Northwest 16th Avenue that closed its doors last year.  Portland Fire & Rescue says firefighters had to battle the flames from outside because holes in the first floor made conditions too dangerous.  Investigators are trying to determine the cause of the two-alarm fire.