@Coinslayer: Nice find... in a way. Congrats! :-)
This is rather interesting, not only for crypto, but also for all open source projects; having a project "open source" and calling the myth of "open source is more secure" doesn't make the code more secure.. Having developers like yourself actually looking into the code and testing the hell out of every possibility is what makes it secure.
Having many people examine the code is only possible with open source. So in general that makes open source software more secure and less bug-ridden than closed source software. This is well-known.
Obviously, making a piece of software open source doesn't automatically make it more secure. While the discovery of the OP is quite desastruous for NMC, think about how much bigger the desaster would have been if the bug had been discovered by some black hat in a year or two because (?) the project was closed source.
Now the devs (assuming there are some left, but there seems to be *some* activity over at dot-bit.org) have a chance to fix the issue and bring the project back to where it's useful. I think the ideas behind NMC are quite cool, especially because this way namecoins and the NMC blockchain do have an intrinsic value, in contrast to all the other alts.