I've been trying things for weeks now, searched thoroughly in google many times but can not find the answer. Here is the script:

// Check to see if the banner ID flag is set
if(isset($_bannerID)) {

// Create an instance of the Database Layer

$DB = new DB_BANNER;

// Get info about banner from DB

$DB->query("SELECT * FROM banner
WHERE(uniqueid=$_bannerID)");

// Check to see if Banner ID is valid before doing
// anything else

if($DB->num_rows()!= 0) {

// Increment Click Counter

dbIncClks($_bannerID);

// Redirect user to new location, $_query_extra
// is the Extra parameters that were given to the
// script back in dbShowBan(). This feature is
// for if you want a banner on your own site, to
// your own site, but use sessions and don't want
// the user to lose their session when they
// click.

$url = $DB->f("URL"). $_query_extra;
Header("Location: $url");

}


}

function Display_Banner($bannerID = "none",
$query_extra = "") {

// Grab the Database Layer and the Config options

global $DB, $_bannercfg, $PHP_SELF;

// Did we pass a BannerID?

if($bannerID == "none") {

// If Not, Grab the next in rotation

// First, make sure that there is something to select

$DB->query("SELECT * FROM banner WHERE pos=''
LIMIT 1"); /* L I N E 8 2*/

// If there is nothing, then everything has
// been displayed
// Time to start from square 1

if($DB->num_rows() == 0) {

$DB->query("UPDATE banner SET pos='' WHERE(pos='A')");

}

// Finally, select the next banner

$DB->query("SELECT * FROM banner WHERE(pos='')
ORDER BY b_order LIMIT 1");


} else {

// If so, Grab the requested Banner

$DB->query("SELECT * FROM banner
WHERE(ID='$bannerID')");


}

// Make sure we grabbed something

if($DB->num_rows() == 0) {

return false;
}

$DB->next_record();

// Saved the data we got in a separate array

$ban_data = $DB->Record;

// Construct the HTML for the GET

$get = "?_bannerid=".urlencode($ban_data['ID']);

// Make the extra query string

if(is_array($query_extra)) {

foreach($query_extra as $key => $val) {

$get .= "&$key=".urlencode($val);

}

}

// Construct the HTML for the banner and include the GET // we constructed previously.

$html = "<a href='$PHP_SELF$get' target=\"_blank\">"
. "<img src='$_bannercfg[srcpath]$ban_data[SRC]' "
. "alt='$ban_data[ALT] "
. "border='$_bannercfg[border]'>"
. "</A>";

// Increment the hits
dbIncHits($ban_data['ID']);

// Flag the banner used as displayed (if it was selected
// by rotation) In special cases, we're not going to flag
// anything

if($bannerID == "none") {

$DB->query("UPDATE banner SET pos='A'
WHERE(ID='".$ban_data['ID']."')");

}

// Finally, echo the HTML

echo $html;

// Return True

return true;

}

function dbIncClks($_bannerID) {

global $DB;

$DB->query("SELECT clicks FROM banner
WHERE(ID='$_bannerID')");

if($DB->num_rows() == 0) {

return false;

}

$DB->query("UPDATE banner SET clicks=".($DB->f('clicks')+1)." WHERE(ID='$_bannerID')");

}

function dbIncHits($_bannerID) {

global $DB;

$DB->query("SELECT hits FROM banner
WHERE(ID='$_bannerID')");

if($DB->num_rows() == 0) {

return false;
}

$DB->query("UPDATE banner SET hits=".($DB->f('clicks')+1)." WHERE(ID='$_bannerID')");

}

And I get the following area:

Fatal error: Call to a member function on a non-object in /home/.../public_html/adrotator.php on line 82

On the page I want it to display I am including this file and using:
display_banner();

Thanks.