Nimmermehr7 - alternatively you can fix it yourself by editing the project XML data. Rename a .capx to .zip and extract the files to convert it to a folder project, then remove any of the XML tags it complains about. They will be events referring to an empty family.
We had to do this in order to fix a bug which could crash the editor, but as a side-effect there are a small minority of projects that have events referring to an empty family that need updating. Either you can fix them yourself as described above, or if you are happy to send us your project then we can do it for you. This will only ever need to be once, and then it can never happen again since we fixed the associated bug. The end result is Construct 2 is more reliable, since the new versions are less likely to crash, but unfortunately this workaround is necessary in the transition.