I am seeing the same error. I tried a fresh install of SilerStripe 2.2.2 but the bug is persistant. Is there any specific requirements on the server side to run the security section. I am using an Ubuntu server.
Need more details in server? Any ideas on what's wrong? Thanks.
I did two things.
First I increased the memory_limit in /etc/php5/php.ini from 20M to 32M. This was recommended by the Silverstripe install page.
This did not make the Security tab in my 2.2.2 site work.
Then I installed Silverstripe 2.0.2 sr2 the same way, on the same server.
The security tab in 2.0.2 works fine now.