why does this show up blank?

[N!ck]

this generates a blank page when i access it without a query string even...anyone know why?

PHP Code:

<?php
require("../forums/global.php");
if ($action=="upload") {
  if ($folderid=="") {
    eval("standarderror(\"".gettemplate("error_gallery_nofolder")."\");");
    exit;
  }
  if ($caption=="") {
    eval("standarderror(\"".gettemplate("error_gallery_nocaption")."\");");
    exit;
  }
  if ($picfile=="") {
    eval("standarderror(\"".gettemplate("error_gallery_nopic")."\");");
    exit;
  }
  $picsize=getimagesize($_FILES['picfile']['tmp_name']);
  if ($picsize[0]<200) {
    eval("standarderror(\"".gettemplate("error_gallery_pictoosmall")."\");");
    exit;
  }
  if (!eregi("jpeg",$_FILES['picfile']['type'])) {
    eval("standarderror(\"".gettemplate("error_gallery_invalidtype")."\");");
    exit;
  }
  $securitycheck=$DB_site->query_first("SELECT * FROM galfolder WHERE galfolderid='$folder'");
  if ($securitycheck['userid']!=$bbuserinfo['userid']) exit;
  $DB_site->query("INSERT INTO galphoto (galphotoid,galfolderid,caption,dateline) VALUES ('0','$folder','$caption','".time()."'");
  $pictureid=$DB_site->insert_id();
  if ($picsize[0]>500) {
    $aspectratio=$picsize[0]/500;
    $newwidth=500;
    $newheight=round($aspectratio*$picsize[1]);
  } else {
    $newwidth=$picsize[0];
    $newheight=$picsize[1];
  }
  $srcimg=imagecreatefromjpeg($_FILES['picfile']['tmp_name']);
  $dstimg=imagecreatetruecolor($newwidth,$newheight);
  imagecopyresampled($dstimg,$srcimg,0,0,0,0,$newwidth,$newheight,$picsize[0],$picsize[1]);
  $color=imagecolorallocate($dstimg,0,0,100);
  $fontx=$newwidth-100;
  $fonty=$newheight-6;
  imagettftext($dstimg,14,0,$fontx,$fonty,$color,"../images/fonts/serpentine.ttf","V-Driveboat.com");
  imagejpeg($dstimg,"../images/gallery/photos/".$pictureid.".jpg","100");
  imagedestroy($dstimg);
  $naspectratio=80/$picsize[0];
  $newheight=round($naspectratio*$picsize[1]);
  $thmimg=imagecreatetruecolor(80,$nheight);
  imagecopyresampled($thmimg,$srcimg,0,0,0,0,80,$nheight,$picsize[0],$picsize[1]);
  imagejpeg($thmimg,"../images/gallery/thumbs/".$pictureid.".jpg","100");
  imagedestroy($thmimg);
  imagedestroy($srcimg);
  eval("dooutput(\"".gettemplate("gallery_uploaddone")."\");");
  exit;
}
eval("dooutput(\"".gettemplate("gallery_upload")."\");");
?>