[function.fopen]: failed to create stream

I am trying to read the contents of a simple text file. However I receive the following error:

Warning: fopen(C:\Temp\testdata_azl.txt) [function.fopen]: failed to create stream: No such file or directory in C:\Inetpub\wwwroot\azl\setup.php on line 77

I have read the URL
page and am fairly certain that this is due to 'permissions':
If PHP has decided that filename specifies a local file, then it will try to open a stream on that file. The file must be accessible to PHP, so you need to ensure that the file access permissions allow this access. If you have enabled safe_mode, or open_basedir further restrictions may apply.

The code I'm using is as follows:
<?php
$filename = "C:\\Temp\\testdata_azl.txt";
echo ("\$FILENAME: $filename");
$handle = fopen ($filename, "r");
$contents = fread ($handle, filesize ($filename));
fclose ($handle);
?>

Could there be any other reason other than a permissions issue which might throw up this kind of error message?

Any useful comments would be greatfully received.
Thanks,
Andy

try using the chmod on the file before you open it

chmod(file path, 777);

its either your path is wrong, or your permissions. however if its on windows, its more to be the path.

Thanks Ben,
I was [stupidly] forgetting that I needed to give the file path as if I were sat @ the Web server [eg. C:\Inetpub\wwwroot\azl\testdata_azl.txt] I use and not the file path as when I am sat @ my local machine [eg. C:\Temp\testdata_azl.txt].
Thanks for your help.
Andy