Interview question: Why are you looking for a new position so soon?

Context: For the last 7 months, I've been an exec at a software company and have over-delivered in a measurable fashion, and have been recognized for my performance, and the company has grown due to my efforts.

Problem: Company has not met the terms of my contract due to poor financial management and planning - they're in breech, but I have no desire to escalate to legal (for many I assume to be obvious reasons). Rather, all cool - I'm just going to move on and try not to make the same mistake again. 

Question: I'm interviewing for leadership roles in marketing. What is the best way to answer the question " Why are you leaving your current position only seven months after hiring on?"

My gut answer has been one of restrained and respectful honesty: "Current company hasn't met the terms of our deal". When questioned further, I've replied: "It has to do with funding". 

Any opinions on this? I don't want to hurt my current company in any way by having a rumor get out that they don't have their i's dotted and t's crossed - rather, I'd like them to get past their problems and succeed. Also, I don't want to mis-represent myself as someone with a short leadership-attention span... but a breech is a breech, they haven't corrected the problem when given the chance, and my skills have a deep value in the current marketplace.

Any thoughts or advice on how to answer this question in an interview would be greatly appreciated.