It seems like you created your forum account before we switched to the current registration method. All accounts that were created that way need to be upgraded through the in-game form to be able to access the MoronYard explorer.
To do so, open the form in-game via the /register command, then click the "I already have an account" option. At this point, you only need to enter your log-in information into the form to verify your account.
Afterwards, you should have access to all the explorer features!