How to add dimensions in account pyramids

Hello Everyone,

Is it possible to add Dimensions in account/nominal  ??

I am able to add dimension under account 31100 (on screen). However, when I click on SAVE button, it throw error "Error in pyramid 31100" and records didn't save in database. 

Screen 1 - where I can add Dimension in account.

Screen 2 . Error when I click on SAVE button.

Thanks in advance!