(5s):249.1M (avg):399.4Mh/s | A:1 R:0 HW:968 WU:3.5/m
ST: 3 SS: 0 NB: 40 LW: 3298 GF: 0 RF: 0
Connected to ***snipped***
Block: ***snipped***... Diff:65.8M Started: [07:38:59] Best share: 873
--------------------------------------------------------------------------------
Pool management Settings Display options Quit
AMU 0: | 364.4M/399.4Mh/s | A:1 R:0 HW:968 WU: 3.5/m
A: Number of shares accepted by pool
R: Number of shares rejected by pool
HW: Number of hardware errors resulting in invalid shares generated.
This number should be zero, or at least very small compared to A+R, something is wrong with your setup.
Try pointing a fan at the block erupter, in case the problem is heat-related.
It could also be that you have a poor quality powered hub, which is not providing a good/consistent power supply.
You may find some useful information in this thread:
https://bitcointalk.org/index.php?topic=220905.0