Upgrade/database problems from 3.8.1 - 3.8.4
 

My web server recently upgraded to MySQL 5 and I had problems with my vBulletin. For example, if someone clicked 'new posts' and there were none, it would give an error:

Could not find phrase 'searchnoresults_getnew'.

I was running vBulletin 3.8.1 so I thought perhaps upgrading would solve the problem. I've gone through the usual steps when running the upgrade script I have the following error at 'Step 2) Import latest admin help':

Importing vbulletin-adminhelp.xml
Database Error Database error

Code:
Database error in vBulletin 3.8.4:

Invalid SQL:

DELETE FROM phrase
WHERE product IN ('vbulletin', '')
AND fieldname = 'cphelptext'
AND languageid = -1;

MySQL Error : Incorrect key file for table './twentyma_VB/phrase.MYI'; try to repair it
Error Number : 126
Request Date : Tuesday, February 2nd 2010 @ 06:04:40 PM
Error Date : Tuesday, February 2nd 2010 @ 06:04:41 PM
Script : http://URL/forums/install/finalupgrade.php?step=2
Referrer : http://URL/forums/install/finalupgrade.php?step=1
IP Address : xxx.xxx.xxx.xxx
Username :
Classname : vB_Database
MySQL Version : 5.0.89-community
I've tried repairing the table via my Control Panel and via PHPmyadmin and get the error:

twentyma_VB.phrase
Error : Table './twentyma_VB/phrase' is marked as crashed and should be repaired
Error : Table 'phrase' is marked as crashed and should be repaired
status : Table is already up to date

And in PHPmyadmin it says the table is 'in use'.

I haven't got a clue what to do next. Any advice much appreciated. Thanks