Database Error Number: 1191 (vBulletin 3.8.0)

[yotsume]

I moved my site from one host to a new one. Import of the database went fine. Everything works except for similar thread searches. It gives a database error.

I receive database errors when performing searches for similar threads.

Also I receive the following database error shown below in my admincp when I try to update counters: "Rebuild Similar Threads".

I have tried a number of solutions but none have worked so far.
I tried:
-Changing the search type (didn't work)
-Emptying and Rebuilding Search Index (didn't work)

Here is my database error:

Database error in vBulletin 3.8.0:

Invalid SQL:

                        SELECT thread.threadid, MATCH(thread.title) AGAINST ('Training') AS score
                        FROM vb_thread AS thread
                       
                        WHERE MATCH(thread.title) AGAINST ('Training')
                                AND thread.open <> 10
                                 AND thread.threadid <> 20
                               
                        LIMIT 5;

MySQL Error   : Can't find FULLTEXT index matching the column list
Error Number  : 1191
Request Date  : Monday, December 2nd 2013 @ 01:41:22 PM
Error Date    : Monday, December 2nd 2013 @ 01:41:22 PM
Script        : http://www.mydomain.com/emr/admincp/misc.php?do=updatesimilar
Referrer      : http://www.mydomain.com/emr/admincp/misc.php?do=chooser
IP Address    : 
Username      : 
Classname     : vB_Database
MySQL Version : 5.0.91-community

What can I do to my database to fix this error? I can not make and new threads on my site.

Can anyone help me to fix the error in my database please.

--------------- Added [DATE]1386029989[/DATE] at [TIME]1386029989[/TIME] ---------------

My second error is when I try to make a new thread. I get this error:

Database error in vBulletin 3.8.0:

Invalid SQL:

			SELECT thread.threadid, MATCH(thread.title) AGAINST ('test post') AS score
			FROM vb_thread AS thread
			
			WHERE MATCH(thread.title) AGAINST ('test post')
				AND thread.open <> 10
				
				
			LIMIT 5;

MySQL Error   : Can't find FULLTEXT index matching the column list
Error Number  : 1191
Request Date  : Monday, December 2nd 2013 @ 05:05:50 PM
Error Date    : Monday, December 2nd 2013 @ 05:05:52 PM
Script        : http://www.mydomain.com/emr/newthread.php?do=postthread&f=7
Referrer      : http://www.mydomain.com/emr/newthread.php?do=newthread&f=7
IP Address    : 
Username      : 
Classname     : vB_Database
MySQL Version : 5.0.91-community

What do I need to do to my database to fix this???