Hi bigbubble--
It's funny, it seems like your biggest issue might simply be lack of confidence!! You say that you have a startup that's not been too successful, yet you have 20 employees!! That's sort of a big deal if you ask us - maybe you haven't broken into the big time yet, but you gotta be doing OK!
The bschools will be evaluating your experience much more than the outcomes. They'll be interested in the fact that you've launched this business and grown it to this particular point. There's lots of people who never even make it that far! You'll be able to pull from this great foundation of relevant and practical experience in everything that you do going forward. Plus, you'll probably be able to add value to classroom discussions and to even possibly help other students who are interested in entrepreneurship but have never done their own thing before. So, your profile could be quite appealing to a bschool adcom, if it's positioned the right way.
In fact, you might be able to easily show the adcom why you want to get an MBA, if you feel that you are being held back from greater success because of the lack of formal training. That sounds like a perfect recipe for why an MBA makes sense for you! Many people struggle to articulate why they need an MBA, but for you, it looks kinda obvious!
Anyway, you should feel confident that you've got the right elements in your profile that will be appealing to certain adcoms, and now it's just a matter of identifying which schools are the right match. If you want to stay in Europe, then we'd recommend the schools we named before: INSEAD, IMD, maybe LBS. There are plenty of other good schools too like Oxford Said and Cambridge Judge, or HEC Paris. Based just on what you've shared so far, INSEAD would be the first recommendation, since it's an awesome program and they have good support for entrepreneurs based on the "roots" of the school and their founder.
If you want to research American schools, then some of the ones named by the other poster *might* be appropriate, though NYU and UCLA both would be a tough nut to crack - Stern is most definitely a Top 10 school and they are *very* competitive, as is Anderson. (Schools like Olin, Babson, and Kelley cannot touch Stern and Anderson, they're in a different category, it doesn't make sense to even group them together.) As already mentioned, you're quite a bit older than the average American bschool student so it's gonna be tough for you if you want to come across the pond. It didn't sound like you were that interested in the U.S. programs anyway so EssaySnark isn't gonna waste a bunch more time on them, but we can explore further if you are interested.
Bottom line: You have elements in your that can absolutely work in your favor, you should push forward with your research and try for some applications this year!!!
Best of luck,
EssaySnark