Fatal error with Contact Form 7 enabled

Who are you using for your web host? Different web hosts have limits on available memory – you could try adding this to your wp-config.php file:

define(‘WP_MEMORY_LIMIT’, ‘256M’);

Thank you. I tried your suggestion but no results so far.
My limit is 64m…

OS Type Linux vs10721 2.6.32-5-vserver-amd64 #1 SMP Fri May 10 10:52:10 UTC 2013 x86_64
Server Software Apache/2.2.16 (Debian)
PHP Version 5.3.3-7+squeeze16
MySQL Server 5.1.66-0+squeeze1
Memory Limit 64 MB

Any other idea?

Who is your web host?

You could login via FTP (preferably SFTP) and see if there’s a php.ini file at the root – if so, open it and look for something defining the memory limit, like this:

memory_limit = 64M ; Maximum amount of memory a script may consume (64MB)

Edit that line and change the 64M and 64MB to 128M and 128MB respectively.

If there’s no php.ini file you could try adding one by using a plain text editor and putting in this line:

memory_limit = 128M ; Maximum amount of memory a script may consume (128MB)

then save it to the root of your site via FTP (SFTP)

Some hosts don’t allow this or won’t obey the php.ini file in which case your only real option is to get a better host.

https://www.mijndomein.nl (its dutch)
It’s not possible to edit php.ini because it’s not there. I think I just need to look for a better host…