1. Multi-GPU: I tested miner on Ubuntu and Cent, on a system with 3 GPUs and I cannot duplicate this issue. So it must be something related to Catalyst version, or to Linux version that you use.
2. "Input OpenCL binary is not for the target!" error is not related to memory allocation error. It means that Catalyst cannot compile kernels, I can duplicate this issue only if I try to start miner for Catalyst 13.12 on the system with Catalyst 14.x or vice versa.