fputs VS fwrite help

[Anon]

Hi,
I am trying to write some variables to a file and here is the delema:

echo $d;
$what="$a|$b|$c|$d"."\n";


$file2=fopen("pathtofile.txt","w");
$fp=fwrite($file2,$what,4096);
fclose($file2);

The above DOESN'T work....but this does:

$what="$a|$b|$c"."\n";


$file2=fopen("pathtofile.txt","w");
$fp=fwrite($file2,$what,4096);
fclose($file2);

I know $d exists...because I can echo it out before I'm adding it to the string, as seen above. Any idea why this last variable doesn't get included in the string? I can replace the $d="varible from the web" with
$d="hard coded text" and it works just fine.

I'm on an Apache server.

Any ideas??

[Anon]

P.S. I've also tried fputs with the same results.

[Anon]

The script that is trying to write to the file is a child window created by javascript with newwin().
Could this be the problem? The child window can't write to a file??