I cant play the police side missions in gta 4 TBoGT!!!!!!!!?

Whenever i get into a police vehicle (Police Patrol, Police Cruiser, NOOSE Patriot, NOOSE Cruiser, and the FIB Buffalo) and i go to the side missions or the current crimes/most wanted it says " ERROR CONNECTING TO SERVER. PLEASE TRY AGAIN LATER." I don't know what to do! Please Help!!!!!