Please check the thread I linked in my previous response - When you log in to the forums, make sure to select the 'Remember Me' option and you should not experience this problem. We are looking in to why that is and we hope to have a solution soon. If for any reason selecting that option on login is not helping, feel free to get in touch with support directly (support@artrage.com) and we'd be happy to help.
Because there's already a thread dealing with this, linked above, we've closed this one.
Matt
ArtRage UI
Ambient Design.