Correct; I get the same when the AMD driver crashes and recovers. Quitting Cgminer and restarting it will allow you to start mining again.
Back off on your overclock a bit. Cgminer pushes your cards a bit harder than some other miner programs, and you can usually achieve the same or better hash rate with a lower overclock.
Not in my case. Overclock down less Hashrate.
It would be great if author would make autorestart programm, after driver crash in next version of Cgminer.
Well of course a lower overclock will get you lower hashrates. What he's saying is that CGMiner at a 920MHz OC might be equal to another program at a 940MHz OC.