It is a notice and not an error.

For me it looks like you have an array and try to access a key, which does not exist (yet)

Here is an example:
<?php
$try = array();
echo $try["no_key_here"];
?>

So, your key "language" is not set/has no data.

Your script has output before it can change the HTTP header data.

In most cases, you just have a blank before your opening <?php tag

Or you do a "echo" before session_start()?

If my hints don´t help, please post some more code...

Please see
http://www.bala-krishna.com/php-fatal-error-fix-cant-use-method-return-value-in-write-context

Could you please post your error message?
Perhaps you are not allowed to open the file, or you have a typo in the file path, or safe_mode is in effect, or you try to open a url and your server settings do not allow it, it could have plenty of reasons.

So please give us some code...

this error appear in this case, for example:

<?php

$object = new Object();

if( isset($object->getParam()) ){
die('ok');
}

?>

"What is phpBB?

Since its creation in 2000, phpBB™ has become the most widely used Open Source forum solution."

This error means, that admin/webmaster of a website made a mistake in their forum software. This should be noticed an repaired soon, so just try again later.

Could you please paste the exact error message? Otherwise i can´t help you.

Do you have:
<form enctype='multipart/form-data' ... >

for uploading files?

You have a time limit for script execution. Your script exceeded this time limit.

You can try to set an own time limit using the function:
set_time_limit() e.g.:
<?php
set_time_limit(30); //extend it to 30 seconds

In most cases this won´t work because it is forbidden by your webserver-configuration to override the setting.

Ask your provider to kindy raise the max_execution_time directive in php.ini

HTH, Max

Try adding the following line to your httpd.conf:

LoadModule suexec_module /usr/lib/apache2/modules/mod_suexec.so

It does not matter, which module you load here. PHP needs to find a "LoadModule" string and I believe your httpd.conf was simply empty

HTH

Have a look at http://php.net/include/