sorting failed error

[Jonathan M Davis]

On Monday, July 30, 2012 14:36:07 maarten van damme wrote:
> I have no idea what is wrong with my code and the error is not very
> informative. Does anyone have any idea as to what the problem could be?

My first guess would be that your sorting function is not antisymmetric. I ran 
into such an issue recently:

http://d.puremagic.com/issues/show_bug.cgi?id=8469

- Jonathan M Davis