I have seen this once before and it took a reboot to get my locals back. Have you done a reboot? IF not do one of these;
power button reboot-push and hold power button on receiver till it reboots.
power cord reboot-pull the plug ,wait 30 seconds to a minute , plug back in.
smart card reboot-pull the smart card and reinsert it.
If all else fails call DISH and ask the tech department what's up. Also try the following email for any picture /audio problems on locals or any dish channel; dishquality@echostar.com