strange problem

[deepmob]

there is a member who got strange problem in my forum, and he want it to fix me,

the problem is when ever he is posting something, its just getting doubled that post,

its happening with him only, what the possible mistake he had make.

[Jake Bunce]

Is he clicking the submit button twice?

I have seen problems like this on forums that have the flood check disabled. Make sure this isn't set to 0:

Admin CP -> vBulletin Options -> Message Posting and Editing Options -> Minimum Time Between Posts