Fresh install of vb3.01 on server (no upgrades, just a clean install).

When posting a new thread, after submit it comes up with the:

"The following errors occurred when this message was submitted:
  1. Please complete both the subject and message fields. Press the back button, correct the problem and try again.
  2. The message you have entered is too short. Please lengthen your message to at least 10 characters.
"

Message.

What would cause this?