os x lion

[mich]

I installed os x lion on my Imac 2009 model. I wanted I cloud on all my macs and devices. I had snow leopard 10.6.8 unfortunately Time Capsule was not backing up recently, one of data bases will not open with Lion. I need it for work. Can I uninstall Lion and re-install with my Snow Leopard disk, or create a partition and move Lion to it for using Icloud. It works fine with my Macbook Pro Iphone and Ipad2. I put it on the IMAC because that is where I enter all my Ical and address book info. The data base is book inventory, the software worked with Windows and Snow leopard, now it will no open. There is a version that works with Lion, however my last back-up on Time Capsule is from August, I did not notice it was not back up automatically. I have been all over the internet, the solutions are complicated and seem over kill for MAC. Any help will be much, much appreciated.