The game will not allow you to register while using Robotic Arm 3 and also the Cosmic Corsair Hook Left gloves. I tried with all of the hook variants (I initially wanted clean, but tried with large hook, etc). If you try to load the saved costume, it will give you a glove error and the fix will replace your gloves (usually). I've tried the hook with other upper body variants and other robotic arm variants and they worked fine.
Uneducated guess: The game is having a problem finding the glove for the right hand in Robo Arm 3 (Full right arm skin).
Thanks!
(I went with Pirate hook, I look forward to changing it once this bug is fixed).