Did you change anything on the pool? Sounds like a temporary pool error. Try rebooting it and see if it keeps doing the same thing (and check Litecoinpool.org to rule out pool issues if you running on a different pool). If that doesn't work try an SD card re-flash.
I did reboot several times and also checked different pools and all had the same problem. After running for a few hours it has gotten better but still is only hacking at 90 MH/s with still 5% hardware errors.