I have a similar problem on with CGminer on Linux. Whilst mining BTC is fine, and I compiled cgminer with scrypt enabled, as soon as I use

./cgminer --scrypt _other_options_and_pool_info

cgminer almost immediately segfaults.

Is there another GPU miner for Linux other than cgminer and Litecoins I could try to compile that would work well with ATI Radeon 7850's and 7950's?