Lost Library after upgrade

I have no pictures/files showing up at all in the new version. After I loaded some pictures from my camera, suddenly all the files were there except that I get an error message "that picture can't be found when I attempt to work with individual photos.
Now after no having used the program for a few days the same problem nothing seems to be in the library at all.
Neither can I use my backup because that was made before I installed version 2.1.
Will I have to re-install the old version to access my pictures?
Please help as otherwise I have lost thousands of photos