Warning: file() [function.file]: Filename cannot be empty. Why? - php

Question

When I am going to submit this (Warning: file() [function.file]: Filename cannot be empty) warning shows. How can I solve this problem. Please help I am new in php. Email has been sent but files doesn't attach. I want to sending mail with attach with raw php.
may code is look like this:
$tmpName = $_FILES['attachment']['tmp_name'];
$fileType = $_FILES['attachment']['type'];
$fileName = $_FILES['attachment']['name'];
/* Start of headers */
$headers = "From: $fromName";
if (file($tmpName)) {
/* Reading file ('rb' = read binary) */
$file = fopen($tmpName,'rb');
$data = fread($file,filesize($tmpName));
fclose($file);
/* a boundary string */
$randomVal = md5(time());
$mimeBoundary = "==Multipart_Boundary_x{$randomVal}x";
/* Header for File Attachment */
$headers .= "\nMIME-Version: 1.0\n";
$headers .= "Content-Type: multipart/mixed;\n" ;
$headers .= " boundary=\"{$mimeBoundary}\"";
/* Multipart Boundary above message */
$message = "This is a multi-part message in MIME format.\n\n" .
"--{$mimeBoundary}\n" .
"Content-Type: text/plain; charset=\"iso-8859-1\"\n" .
"Content-Transfer-Encoding: 7bit\n\n" .
$message . "\n\n";
/* Encoding file data */
$data = chunk_split(base64_encode($data));
/* Adding attchment-file to message*/
$message .= "--{$mimeBoundary}\n" .
"Content-Type: {$fileType};\n" .
" name=\"{$fileName}\"\n" .
"Content-Transfer-Encoding: base64\n\n" .
$data . "\n\n" .
"--{$mimeBoundary}--\n";
}
echo $message;
$sendmail = mail ("$to", "$subject", "$message", "$headers");
if($sendmail){
echo "A email has been sent to: $to";
}
else{
echo "Error in Email sending";
}
}

Answer 1

if (file($tmpName)) {
You probably want if (file_exists($tmpName)) {?
Also make sure $tmpName is actually filled out.