Ed:

Since it is the index.php file that is causing the trouble
this is what I have.

Just below:
if ($action=="showforums") {

I have:

//PM HACK
if ($bbusername) {
$username = $bbusername;
$pmcounta = $DB_site->query_first("SELECT COUNT(msgid) AS msgid FROM privatercvd WHERE toid=$bbuserid");
$pmcount = $pmcounta[msgid];
$newpmcounta = $DB_site->query_first("SELECT COUNT(msgid) AS msgid FROM privatercvd WHERE toid=$bbuserid AND UNIX_TIMESTAMP(datetime)>$bblastvisit");
$newpmcount = $newpmcounta[msgid];
if ($newpmcount == 0) {
$lightbulb = 'images/off.gif';
} else {
$lightbulb = 'images/on.gif';
}
$lastsent = $DB_site->query_first("SELECT fromid,UNIX_TIMESTAMP(datetime) AS datetime FROM privatercvd WHERE toid=$bbuserid ORDER BY msgid DESC");
if ($lastsent) {
$lastid = trim($lastsent[fromid]);
$lastdate=date($dateformat,$lastsent[datetime]+(($timeoffset+$bbtimezoneoffset)*3600));
$lasttime=date($timeformat,$lastsent[datetime]+(($timeoffset+$bbtimezoneoffset)*3600));
$lastsentuser = $DB_site->query_first("SELECT username FROM user WHERE userid=$lastid");
$lastuser = htmlspecialchars($lastsentuser[username]);
}
eval("\$pminfo .= \"".gettemplate("pmloggedin")."\";");
} else {
eval("\$pminfo .= \"".gettemplate("pmloggedout")."\";");
}
//END PM HACK

and this is just above:

$numbersmembers=$DB_site->query_first("SELECT COUNT(userid) AS users FROM user");
$numbermembers=$numbersmembers[users];

Does this look right?

Parker