Registration Issue

[hirebuysell]

Hi,
There is problem with our board when someone try to register on our forum when they click to complete registration nothing happens and they redirect to index.php
here is our forum url:
http://forum.howtogrowmarijuana.com/
I tried to add new style "Default vBulletin" but error is still there.
please suggest us the solution.
Thanks in advance

[ForceHSS]

Do you have facebook option on but no info filled in. Check server error logs as well

[hirebuysell]

Do you have facebook option on but no info filled in. Check server error logs as well

Well there is no error log as well as facebook option isn't enabled.
What it seems to be ? any idea ?

[hirebuysell]

Bump , no reply :( please help

[ForceHSS]

When you say no error logs were are you checking for this info