I think in every part of our life we have some failures, whether or not it's in a social enterprise. It's important to handle and learn from them so that these never happen again. Ofcourse learning from failing means that the next time we will fail in a different way. ;)
It's important how we handle our failures before, during, and after it happend. Sometimes in a well planned process you can see the flaws and can prepare for them.
Maybe you had a SWOT analysis or you work in a 5 year long project with every detail pre-planned and some elements change. It's good to know when things will fall apart so you can prepare for them. There are also times when you can't see what will happen and the process takes a wrong turn. At that point most of the people start to panic and make quick decisions, I've done it myself too. It's hard but in these times you have to slow down and take the time to think trough the problem you facing. When the problem is over it's important to sit down again and check each part. What was your mistake? What was the other persons mistake? What was a systematic mistake? Just be sure not think too much about it. Try to be as objective as possible, it makes decision making a lot easier.
In any time at the process you should consult with an outsider, a friend, a professional, a teacher. It's nice to have someones objective opinion. It gives you another perspective which you might not even considered.
And don't forget to let it go. Don't think about it too much afterwards, just learn from the consequences and move on. Even if someone fails horribly and loses everything there is always another place to start over.
That was some of my ideas, feel free to add something or disagree with me, a good disagreement can be the engine of productivity and learning!