Having ffixed our clock, people can now not post due to the flood control settin in Master Settings > Feature Settings. This is set to 10. I have tried leaving it blank and as -1 to see if this helped.
Some people can post but those who posted when the time was wrong now cannot.
Ah, there is also a cookie that stores some of that info as well. Basically, anyone that is currently logged in and getting that error, should just close their browser completely and then come back. They should be able to post then.