I had no idea we had a collab board. DerrickEwing and I are doing a collab, but for some reason the site wont allow me add him in on the collab..could some one help me?

Did you try to just put the number instead of the name.
And Is It under the file size limit???
If It's set to unfinish hidden then you should be able to change It to the collab board.
Just look on the edit/delete page for It and See if you can change the board.

i did all that..but for some reason it wont let me add any users..

Maybe It's just your computer. Try on a different computer or a Different internet connection.
When I 1st came here my computer wouldn't let me add people on collabs so I used my Computer at school.