It's stating that an attempt to open the file
content1.php and write to it has failed.
For this to work the directory housing the file ('home') has to have suitable permissions available.
You can set the permissions of a directory via your control panel or you ftp client.
As the php/app is failing to initially open the file, the second (write) and third (close) tasks cannot be executed either, so both kick up errors.
The inconsistency will probably be down to permissions being set on some servers/directories, but not on others.
blah, blah:
http://www.htmlite.com/php042.php
http://uk2.php.net/fopen