Changing tax of controlled (sieged) town?

[StrEagle]

I sieged a town, I won it, then I go to change tax, I click change tax, I click 5,10,15,20, it says Tax Changed to: <?tax?>. , and I close the window, when i open it again, i open tax information, and Current Tax Is: .
help? someone has taxing working? or someone knows where I can edit taxing?

[MentaL]

[TuckDaDin]

press tax 20 it says tak. but it works

[StrEagle]

it works 10x