Forum Error in upgrade Forum to version 4.0

[محروم.كوم]

Hello

I have worked to upgrade my forum from 3.8.5 to 4.0

I have created a new database


And deleted all the hooks and plugins And choose Default Style

Then I copy the old database to the new

I have started the installation to step 12 of 13 Showed me an error

PHP Code:
Database error in vBulletin 3.8.5:


Invalid SQL:
ALTER TABLE post ADD INDEX ipaddress (ipaddress);

MySQL Error : 137 when fixing table
Error Number : -1
Request Date : Monday, August 30th 2010 @ 08:13:27 PM
Error Date : Monday, August 30th 2010 @ 08:15:02 PM
Script : http://www.sw-lil.com/vb4/install/upgrade_400a1.php?step=12
Referrer : http://www.sw-lil.com/vb4/install/upgrade_400a1.php?step=11
IP Address : 77.31.89.4
Username :
Classname : vB_Database
MySQL Version :

What are the reasons and why ???

Best Regards __DEFINE_LIKE_SHARE__