I'm using Silverstripe 2.3.3, DataObjectManager r317, and SWFUpload r271 and need to extend a class of objects to include available sizes. Since each particular product will be available in multiple sizes and each size can be available to multiple products I've set them up in a many_many relation.

The problem is that I'm already interacting with the products through a ManyManyDataObjectManager in a ProductHolder page type (class name 'ProductList') and trying to nest the new ManyManyDataObjectManager inside it gives me the following error:
115 on line F:\xampp\htdocs\stinger\sapphire\core\Object.php: Cannot instantiate abstract class Object in Fatal error

What I believe to be the relevant code can be seen here : http://pastie.org/687736

Any thoughts?

Thanks. I plan to transfer the site online from my localhost as soon as I take care of another couple of issues and will do a clean install and update then. Hopefully that will clear it up.

Nope, nothing I can find but that one line. I tried turning on error logging and the same message shows up in the php log.

Oh, man. Don't upgrade to the branch. That's untested. Tons of stuff is going to break. I still haven't gotten all the patches in for the trunk, let alone the branches.