We have a large database in Onfolio.
The last version of Internet Explorer that accepts Onfolio is Internet Explorer 7, but Windows 7 does not accept Internet Explorer 7.
Onfolio is now owned by MS and (most) of it's functionality was incorporated into the Windows Live Toolbar, but as a company/product Onfolio has been dead since about 2008, and won't be upgraded to work with more modern browsers.
It not even officially supported (or expected to work) on IE7 or Vista (let alone Windows 7).
From MS KB956489:
The above MB KB article also includes information on how to export your Onfolio data (to be imported into other applications).
From Wikipedia's entry on the Windows Live Toolbar:
Windows Live Toolbar itself was officially discontinued on March 31, 2011.
Depending on your version of Windows 7, you may be able to get an older version of Onfolio or WLT running in an older version of IE in Windows 7's "XP Mode", or in another VM of some kind.
Unless someone else has a magic hack or fix, then it's probably time to find a replacement product I suppose...
W7 Ultimate x64 w IE11. Download Onfolio from http://download.cnet.com/Onfolio/3000-12512_4-10280499.html (version 1.03) and install on W7 as a free trial. No need to muck with registry. Save the download setup file to rerun after 30 days. I do not know how long this will continue to work.
NOTE: this should help you migrate.
Update: When you re-install activate using sample Onfolio Activation Key. This will tell you the activation server is down, but will let you use the program. IE may give errors until you click the Onfolio button. I recommend you use the desktop version (not within IE). Store your collections outside the Onfolio install folder--you should delete this folder before re-install.