php file problem

[Pouncer]

i keep getting these errors..

Warning: file_get_contents(test): failed to open stream: No such file or directory in /home/prawgzn/public_html/m/remove.php on line 5

Warning: fopen(test): failed to open stream: Permission denied in /home/prawgzn/public_html/m/remove.php on line 9

Warning: fputs(): supplied argument is not a valid stream resource in /home/prawgzn/public_html/m/remove.php on line 10

Warning: fclose(): supplied argument is not a valid stream resource in /home/prawgzn/public_html/m/remove.php on line 11

with the code..

<?php  
$filename = 'test.txt';  
$somecontent = $_GET['data'] . "\n";  

$file_data = file_get_contents($filename);  

$file_data = str_replace($somecontent, "", $file_data);  

$file = fopen($filename, "w"); 
fputs($file, $file_data);  
fclose($file); 

?>