Redirected to install.php after changing prefix

I usually make it a routine to change the my website’s(http://www.suriagroup.com.my) database table’s prefix using your automated feature once per week but after the last changes my website suddenly got redirected to the install.php! There were some errors shown after I changed the prefix but I was in a hurry I didnt bother to look at it properly.All I remembered was something like “taxonomy invalid” or something. I tried some of the solutions I found in the forum but still the problem persist. Here is what I have done:

1. Check the wp-config.php. All ok, the username,password, prefix….

2. Check the prefix in the database. Exactly the same with the settings in wp-config.php

3. Check the home and siteurl in the wp_option table.

4. Check and repair the table.

All of these solutions did not solve the problem. Please help!

http://wordpress.org/plugins/websitedefender-wordpress-security/