Custom Group Rules won't save

Hi,

I'm running Spiceworks V6.1.01100, with several remote collectors. I have created several custom groups but whenever I make a change to the Group Rules and click save, it just hangs on 'Saving...'. I've left it for some time and it doesn't confirm the change and the changes don't persist if I refresh the browser windows later.

I've tried with several browsers (Chrome, Firefox, Safari) on Windows 7 and Mac. Rebooted the server, made sure it wasn't under heavy load etc. Im not having any issues editing devices, creating tickets, it seems to be isolated to the Custom Groups.

There are about 50-100 items that should be matched in each group, with 3 Rules in each group.

Thanks in advance.