It was the fourth of six planned nights at the intimate 1,300 seat theatre, and the L.A. Times reports that the venue was more crowded than even the previous sold-out shows. Apparently, the first sign of trouble came when fire officials kept concert-goers from returning to the theatre from the lobby after getting drinks or going the bathroom.
Around 10:30, Petty himself informed the crowd that 100 people needed to either leave the venue or move up to the balcony, otherwise the show would be cut approximately 45 minutes short. After a long version of the song ‘Melinda,’ he informed everyone that the show was going to have to be cancelled. According to the Times, “the move infuriated fans, who refused to leave amid howls and boos.’
source: ultimateclassicrock.com