There is a limit to the amount of data you can pass in a query string. You might try creating a temp file containing the data and then opening it in the next script like this
$filename = time();
$filename .= ".txt";
touch($filename);
$file = fopen($filename, w)
fwrite($file, $text);
fclose($file);
then you pass $filename in the query string and in the next page you can read the file like this:
$filesize = filesize($filename);
$file = fopen($filename, r);
$text = fread($file,$filesize);
fclose($file);
unlink($filename);
The unlink() function will delete the temp file. The time() function is almost 100% sure to give you an unique filename (unless you have some really odd naming conventions). There are probably other ways to do stuff like this (using a temp space in a database for one example) but this is the one I can think of and tell you how to do (I have only been at this a few months myself and I am not very good at working with databases yet). You might also be able to do it with session functions but I haven't started messing with those yet so I don't know. Also I should note that I am learning and using PHP4 so I have no idea if all of the things I have mentioned work in older versions.