Sorry I can't be more clear!
You might get a better response to your post if you could be.
Just a thought.
In the programming world, things aren't as hush-hush as investors would like them to be. From the limited description of your project I would suspect the following:
1. You are developing a server based product
2. You want to leverage the cost advantages of FOSS so you'll primarily be developing on a NIX platform that allows you to have a restrictive license on your own code while still providing you with license-free use of the underlying platform. I'd be surprised if you didn't decide to go with BSD for exactly that reason. (Using FOSS as a base would also lower your distribution costs, thereby allowing you more flexibility in pricing. In this scenario, your only sunk costs would be for development and marketing.)
3. You're probably planning on doing the bulk of the coding in C++,
4. From #3 above, I'm also guessing your application will make extensive use of NIX system calls, so you'll be using Cygwin to provide Windows compatibility rather than recoding your client module to run natively.
5. From 2,3,and 4 I suspect this project got its start in the academic world; is based on somebody's dissertation or thesis; and most likely began as a project in a graduate program.
6. Your application will make heavy use of calculations, hence the interest in 64-bit Windows.
7. Because you want a non-disclosure up front, your market is probably either in the financial or medical sector. I'm guessing it's a financial forecasting program of some sort since medical apps don't usually require 64-bit firepower.
8. Because you want a non-disclosure up front, you feel your product is intuitively obvious for the need it is addressing, and your investors are afraid that even describing it would be enough for somebody to take your ball and run with it. From this, I would suspect that this product is neither intrinsically patentable nor protectable as a trade secret. Therefor, the business plan is to market very aggressively on product launch in order to secure market 'buzz' and presence before the industry heavyweights and knock-off shops close in.
How'd I do?