Party-hosting duties for DUI suspect Mischa Barton have been put on ice. Her management team - which has been tirelessly working to control the press since "The O.C." star was busted in LA early Thursday morning for drunken driving and possession of narcotics - pulled her from hosting tonight's opening of Cathouse in Las Vegas. "Mischa can't give interviews on the red carpet or deal with the press right now," said a Vegas source, "so they told her she can't do the event." The club was searching for celebrities available at the last minute but was still looking last night.