sometime when i try to post a message it did nothing
 

sometime when i try to post a message it did nothing, i copy the code and paste it in new message and it's work.

Try disabling your modifications/plugins and see if you still have this problem.
Note: To temporarily disable the plugin system, edit includes/config.php and add this line right under <?php

not working, it's happen when i try to edit exist message.
when it's happening i copy the code and paste it in new message and it's work.

So it still doesn't work when you have the plugins off? Keep them off, and then create a new style with no parent:

• Styles & Templates > Style Manager > Add New Style
• Parent Style: No Parent Style
• Title: Default vBulletin
• Allow User Selection: Yes
• Save

Then browse the site using that totally default vbulletin style - do you still have the same problem?

still have the same problem, i try to go to advance or click "delete" or "cancel", it didn't click.
the problem is it didn't click, but when i copy and paste the code to new message it's work, that's very strange.

So, you are using a new default style with no plugins enabled and it still doesn't work? are any default vbulletin files listed in admincp > maintenance > diagnostics > suspect file version?

i have mods install, that's why he wrote about some files "File not recognized as part of vBulletin".