The option in your command "-I 20" is to set Intensity to 20, which is very high for a scrypt coin. Try using "-I 12" This setting may be overloading your card and causing it to crash.
cgminer --scrypt -o stratum+tcp://gld.cryptocoinmine.com:2020 -u WORKER -p PASS -I 12
Yes. Try reducing intensity by units of 1 until you find the "sweet spot".
You might also find useful configuration examples here: http://litecoin.info/Mining_Hardware_Comparison
Thanks guys for the info!