ToME: the Tales of Maj'Eyal

Hey all. I've bought the game on steam and thanks to that, I have a donator status. However, whenever I try to store something in the vault, I always get an error. I've tried multiple types of equipment (ego, unique, artifact, plain) at different times but it never has worked for me.
Is this normal?

Have you connected your te4.org account to your steam account via the option on the te4.org page?

I'm thinking about getting a macro for this...

Your vault might be full! You can't store many items in it, with just a Steam purchase... try withdrawing from it, it'll say it's capacity (e.g 0/3 items stored) at the top.