I have linked SE accounts on stackoverflow (1915 rep), rpg.stackexchange (1030 rep) and others. On meta.stackoverflow, my rep is only 11. Can this be fixed? It should be 100 at minimum because it's a linked account (I should at least get to vote!).
Your meta account was associated more than a year ago, back when none of your accounts had the minimum reputation required for the bonus.
I've cleared and re-associated your accounts, granting you the +100 on meta.so as you now meet those requirements.
Note that fairly recent changes to how associations work has made this a much more difficult state to get into.