Warning : mkdir filetools.inc line 55 - PLEASE HELP

I am having some serious problem with my script.

When I run my script I always got Warning:mkdir filetools.inc line 55

Just so you all know I already have a directory created in my server , I've tried to delete the directory and create it again and but still I am getting that stupid Warning: mkdir error, Please help me anyone.


My line # 55 is

========
     $res=mkdir($filepath,0777);
========

My Whole Script is listed as follows :-
===
<?php
function wrt($filename,$var) {
   $fp=fopen($filename,"w") or goback("cannot write $filename");
   fputs($fp,$var);
   fclose($fp);
}

function append($filename,$var) {
   $fp=fopen($filename,"a") or goback("cannot append to $filename");
   fputs($fp,$var);
   fclose($fp);
}

function rd($filename) {
   $fp=fopen($filename,"r") or goback("cannot read $filename");
   $var=fread($fp,filesize($filename));
   fclose($fp);
   return $var;
}

function wrtarray($filename,$ar) {
   $si=strrpos($filename,"/");
   if ($si===false) $si=-1;
   $ei=strrpos($filename,".");
   if ($ei===false) $ei=strlen($filename);
   $si++;
   $arname=substr($filename,$si,$ei-$si);
   $fp=fopen($filename,"w") or goback("cannot write $filename");
   fputs($fp,"<"."?php\n\$$arname=array(\n");
   if (is_array($ar)) {
      reset($ar);
      foreach($ar as $key=>$val) {
         $key=str_replace("\"","\\\"",$key);
         $val=str_replace("\"","\\\"",$val);
         fputs($fp,"\"$key\"=>\"$val\",\n");
      }
   }
   fputs($fp,");\n?".">");
   fclose($fp);
}

function wrtvar($filename,$var) {
   $si=strrpos($filename,"/");
   if ($si===false) $si=-1;
   $ei=strrpos($filename,".");
   if ($ei===false) $ei=strlen($filename);
   $si++;
   $varname=substr($filename,$si,$ei-$si);
   wrt($filename,"<"."?php\n\$$varname=$var;\n?".">");
}

function makesubdir($filepath) {
   if (!is_dir($filepath)) {
      $oldumask = umask(0);
      $res=mkdir($filepath,0777);
      umask($oldumask);
   } else $res=true;
   return $res;
}

function eraseall($filepath,$pattern="*.*") {
   if (is_dir($filepath)) {
#      foreach (glob("$filepath/$pattern") as $filename) {
#         if (is_file("$filepath/$filename")) unlink("$filepath/$filename");
#      }
      if ($fp = opendir($filepath)) {
         while (($filename = readdir($fp)) !== false) {
            if (is_file("$filepath/$filename")) unlink("$filepath/$filename");
         }
      }
   }
}
?>