ctress Elizabeth Hurley's getting trouble from all sides. Her reputation has suffered a series of setbacks lately. First there was the much-publicized picket-crossing incident during the Screen Actors Guild (SAG) strike. Despite a $25,000 donation and many profuse apologies, the union's still threatening to have her tossed out.   You'd think she'd be on good behavior after all that but Hurley went ballistic when the Lear jet sent by Fox to fly her to L.A. for the premiere of her new flick, Bedazzled, wasn't up to snuff as far she was concerned. And just to show they're not a forgive and forget bunch, as she walked down the red carpet at the premiere, Hurley came face to face with a throng of SAG members carrying their own picket signs hurling insults.   The icing on the cake for the British beauty was the embarrassing press coverage of her very public nuzzling with the very married Denis Leary at the VHI Vogue Fashion Awards recently. The two arrived together looking suspiciously dishevelled.