This issue is due to the system using a new single unified account for the entire site. If you already had a forum account before the merge, follow these steps to sync your accounts:
(Note: If you already had a "main" account before November 2nd that was the same username as your forum username, your accounts should already be linked, and you should not follow the procedure below.)
1. Create a new "main" account by going to Movie-Vault.com and clicking on the "New user? Signup here!" link in the Control Panel section at the top left of the site.
If you already had a "main" account before November 2nd, simply log in.
2. In the Control Panel section located at the top left, click on the My Profile link.
3. Fill out the form in the "Already have a forum account" section at the top of the page. Be sure to enter your forum username and password.
This will change your forum account username to your "main" account username, and should import all of your posts, signature, avatar, etc. The only thing that should change is your username.
Please follow these steps and let me know if it works for you, and if not, please try to reply as detailed as you possibly can so we can help debug this for you.