Big problem!

[Pete C]

My 3.5.4 board is fairly new and has several hacks installed, all of which appear to be working properly. The pm system was tested and working, but since installing one of these hacks (sadly I'm not sure which one) it's failed totally. The system was working prior to installing vBPlaza, but since the subsequent hacks were added within a short time, I can't be sure at which point the system failed.

Whenever I or any member try to send a PM, the following error is generated:

Database error in vBulletin 3.5.4:
 
Invalid SQL:
 
            SELECT pm.*, pmtext.*
                , icon.title AS icontitle, icon.iconpath
            FROM radiocapm AS pm
            LEFT JOIN radiocapmtext AS pmtext ON(pmtext.pmtextid = pm.pmtextid)
            LEFT JOIN radiocaicon AS icon ON(icon.iconid = pmtext.iconid)
            WHERE pm.userid=3 AND pm.folderid=0
            ORDER BY pmtext.dateline DESC
            LIMIT 0, 50;
 
MySQL Error  : Can't create/write to file '/tmp/mysql/#sql_1023_0.MYI' (Errcode: 2)
Error Number : 1
Date         : Monday, July 10th 2006 @ 05:40:25 AM
Script       : http://radio-cafe.com/private.php
Referrer     : http://radio-cafe.com/private.php?do=newpm&u=10
IP Address   : **.***.***.** (edited)
Username     : Belder
Classname    : vb_database

vB ver 3.5.4
Hacks Installed (in this order):

Ajax Shoutbox, V3 Arcade, SHOUTcast on forumhome full, Users online last 24hrs, Show last game installed in what's going on box, Staff colour legend, vBPlaza, vBookie, vbPlaza/vBookie vBux integration, V3Arcade Alternative layout, SHOUTcast Stats moved below Navbar.

My apologies if this isn't in the right place - please feel free to move it guys. Any advice on this will be most appreciated . . . it's a serious problem.

*Update: Just ran a check on the MySQL database and found this line:

radioca_radiocafe.radiocapm                        OK

Clearly it's not ok, and now I'm even more confused - help!