What is your MoBo and CPU? I have the same problem. Two identical rigs on the old 775 socket. But first rig with quad-core CPU core2quad Q8400 (bminer works excellent, about week uptime without errors). The second rig with the same mobo, same GPU's and dual-core CPU core2duo E6750 says "Miner died, restarting" too. On the same time DSTM 0.5.6 and 0.5.7 work fine on this E6750 rig.
This was with an AMD Phenom II 955 and an Asus M4N75TD mobo on Windows 7 - so, completely different!
Still, pretty brazen to charge a devfee for an alpha-level program. I have the same complaint with Claymore's Cryptonight miner, which lies so bad about hashrate it should be made into a rug...