definitely sounds like some sort of mod_security settings. term could be blocked because those are various terminal clients on linux, but that seems extremely anal. form, who knows...maybe because of html forms.
This is becoming very commonplace now. We've had a handful of these problems on ubbcentral and I've worked on at least 5 over the past 2 weeks via ticket. mod_security is pretty evil when it comes to discussion boards since the text within posts can contain just about anything that a host might consider "bad".