what does it mean if one of my posts says its locked and i cant comment on it?

The thread has possibly been deleted making the post non existent or the thread is locked meaning you can read it but that's about it.

Means that a moderator came and locked it off from access. You likely made either a repetitive topic (such as one asking about Dawnguard), or a topic irrelevant to Elder Scrolls.

I think the forum rules explain all you need to know and more.

It means exactly what you said, that you can't comment on it.