Good idea, nice implementation, wrong medium. There is no reason this should be a web application - in a perfect world, I want something like this directly integrated into my database tool, and not have me open my browser and all that. At the same time, considering that the data work may be large, having this on a server is not too bad of an idea. What I suggest to you is this - spend a day to make a version of this…
I think markessien has a great point. A lot of enterprises don't want their office worker in browsers (however lame that sounds) and may not be comfortable sending you their data.
Having a web app style wrapped in a local framework would allow you to sell to these companies what looks to be a really great product.
That said please don't loose the web version for those of us that realize it's the 21st century already.