Multiauthors site fail to store to when add in Tag

Hi,

Recently, I have a site which fails to stores data into the database as soon as the users add in Tags into the post. When the user hit save/publish, the browser freeze, the user have to force to close the browser and when they open it up, the post will be published but not all the content are saved.

This problem never occur in the beginning, but as soon as the site grows (after 6 month time), this problem started to happen. I cannot find any problem related on the web, is there anyone that can help me out?

This only happen when the user add in TAG in the beginning of the post.