After enabling pages, i see the error on attachment. 

i tried reuploading all files and running forum/admin/upgrade without any results. any solutions?

Are you using a custom or modified language pack ? Temporarily switch to the default if you can to see if that cures the "menu_cms_pages_"

You can try running the Support tool in the ACP too, via System > Support > "Something is not working" , keep going until it gets to the stage where it wants you to submit a ticket. Is it any better now ?

If not you'll have to submit a support request in the Client Area so a tech can take a look at this for you.