project "...."was created with cubase.1.x??

My cubase 7 elements crashed while i was working on a project. When I tried to open the project after rebooting cubase, I get the messeage;
Project “…cpr” was created with cubase.1.x
This programversion cannot load it

Why is this?? :cry: And how can I open the project I was working on 5 minutes before?

greets from Amsterdam