why always 500:internal server error???

[true_promote]

I have a php script which runs all fine on localhost,but when I uploaded and run the same script on my web server it gave a internal server error 500,premature end of sdript headers:(null)
But it was running fine on my localhost,file permission set to 755 and I had uploaded the file using my web host's online file uploading system.
What might have been the possible reason for its failure...

the script is below
<?php
//WRITING THE FORMATED AND ALTERNATE RSS INPUT FEED
//writing data onto myrss1 text file
$number=date("d-m-Y");
$f1=fopen("myrss1$number.txt","w");
$f2=fopen("rss1.txt","r");$f3=fopen("rss2.txt","r");
$n=1;
while ($n<=4)
{
$n2=1;
while ($n2==1)
{
$data=fgetc($f2);
if ($data=="^")
{$n2=3;}
else
fwrite($f1,"$data");
}
$n3=1;
while($n3==1)
{
$data2=fgetc($f3);
if ($data2=="^")
{$n3=3;}
else
fwrite($f1,"$data2");
}
$n=$n+1;
}
fclose($f1);
fclose($f2);
fclose($f3);

//writing data onto myrss2 file
$f1=fopen("myrss2$number.txt","w");
$f2=fopen("rss3.txt","r");$f3=fopen("rss4.txt","r");
$n=1;
while ($n<=4)
{
$n2=1;
while ($n2==1)
{
$data=fgetc($f2);
if ($data=="^")
{$n2=3;}
else
fwrite($f1,"$data");
}
$n3=1;
while($n3==1)
{
$data2=fgetc($f3);
if ($data2=="^")
{$n3=3;}
else
fwrite($f1,"$data2");
}
$n=$n+1;
}
fclose($f1);
fclose($f2);
fclose($f3);

//CREATING TWO NEW HTML PAGES
//writing the page 1
$f1=fopen("title1.txt","r");$f2=fopen("description1.txt","r");
$title1=fread($f1,4096);$description1=fread($f2,4096);
fclose($f1);fclose($f2);
$hyip1=fopen("hyip-news$number.html","w");
$read=fopen("myrss1$number.txt","r");
$read1=fopen("htmlpart1.txt","r");
while (!feof($read1))
{
$data=fgetc($read1);
fwrite($hyip1,"$data");
}fclose($read1);

fwrite($hyip1,"$title1");

$read2=fopen("htmlpart2.txt","r");
while (!feof($read2))
{
$data=fgetc($read2);
fwrite($hyip1,"$data");
}fclose($read2);

fwrite($hyip1,"$description1");
$read3=fopen("htmlpart3.txt","r");
while (!feof($read3))
{
$data=fgetc($read3);
fwrite($hyip1,"$data");
}fclose($read3);

fwrite($hyip1,"Latest HYIP News for $number");

$read4=fopen("htmlpart4.txt","r");
while (!feof($read4))
{
$data=fgetc($read4);
fwrite($hyip1,"$data");
}fclose($read4);

while (!feof($read))
{
$data=fgetc($read);
fwrite($hyip1,"$data");
}fclose($read);

$read5=fopen("htmlpart5.txt","r");
while (!feof($read5))
{
$data=fgetc($read5);
fwrite($hyip1,"$data");
}fclose($read5);

fwrite($hyip1,"hyip-news2$number.com");

$read6=fopen("htmlpart6.txt","r");
while (!feof($read6))
{
$data=fgetc($read6);
fwrite($hyip1,"$data");
}fclose($read6);

fclose($hyip1);


//writing the page 2

$f1=fopen("title2.txt","r");$f2=fopen("description2.txt","r");
$title2=fread($f1,4096);$description2=fread($f2,4096);
fclose($f1);fclose($f2);
$hyip1=fopen("hyip-news2$number.html","w");
$read=fopen("myrss2$number.txt","r");
$read1=fopen("htmlpart1.txt","r");
while (!feof($read1))
{
$data=fgetc($read1);
fwrite($hyip1,"$data");
}fclose($read1);

fwrite($hyip1,"$title2");
$read2=fopen("htmlpart2.txt","r");
while (!feof($read2))
{
$data=fgetc($read2);
fwrite($hyip1,"$data");
}fclose($read2);

fwrite($hyip1,"$description2");

$read3=fopen("htmlpart3.txt","r");
while (!feof($read3))
{
$data=fgetc($read3);
fwrite($hyip1,"$data");
}fclose($read3);

fwrite($hyip1,"Latest HYIP News for $number<br/> [page 2]");
$read4=fopen("htmlpart4.txt","r");
while (!feof($read4))
{
$data=fgetc($read4);
fwrite($hyip1,"$data");
}fclose($read4);

while (!feof($read))
{
$data=fgetc($read);
fwrite($hyip1,"$data");
}fclose($read);
$read5=fopen("htmlpart5.txt","r");
while (!feof($read5))
{
$data=fgetc($read5);
fwrite($hyip1,"$data");
}fclose($read5);

fwrite($hyip1,"hyip-news$number.html");

$read6=fopen("htmlpart6.txt","r");
while (!feof($read6))
{
$data=fgetc($read6);
fwrite($hyip1,"$data");
}fclose($read6);

fclose($hyip1);
?>

[koolasia]

Wat u do is when uploading the files do not chmod these files just upload n try

[Pat Gael]

Ask your hosting service, some of them have disable functions like fopen(), fetch, and grab so the will not run.

Otherwise chmod 666 or 777 on txt files as stated by koolasia.

[krakjoe]

If any functions were disabled by the host, you'd get a classic {FUNCTION_NAME} has been disabled for security reasons.

Also, I tried to read through the code, and well it's too much, what is it exactly ?

Lastly, windows machines handle php in an entirely different fasion from a *nix environment, it's never safe to assume that if a script works on localhost that it will do the same in a production environment, if you have a decent machine @ localhost, then install a vm and download the centos server cd, install apache NOT a wampp, lampp or any other kind of ampp, once done you will have as close to a production environment as there is, if your pc isn't good enough to do that, then make a subdomain on your site and use it to test on, obvioulsy eventually you will become acustomed to the things that do and do not work and will have to upload less and less.

In short, I'm not suprised .....