Can't start after Yosemite version upgrade

I upgraded to Yosemite and then upgraded my version of WireframeSketcher. When I try to start it now I get the "WireframeSketcher quit unexpectedly" dialog and am not able to proceed further.

I don't know what the problem was, but I downloaded the latest version and installed it over my previous copy. Now it works. It still shows my license and current projects.

Tad,

We know about this issue, sometimes updates break the app on Mac OS X. Note that your data is unaffected and the solution is to just get the latest version from our website as you did.

I downloaded it again but still doesnt work. Should I update my OS to Yosemite too?

You don't have to update to Yosemite. What is the message that you see now?