The error message "Object length is longer than the physical sample" indicates that something in your saved project has changed.  There are various possibilities:

1. A part of the project has been edited in another program and the size of the file has changed.

2. A part of the project was changed by the system crashing.

3. The name of a file has been changed.

4. There are existing *.HDP or *.H0 files from another project that are causing problems.  To solve this please save the project and movies in an empty folder.

5. It is possible that MAGIX used a different import codec to import the video than the first time.  To solve this problem, open a new project and then import the problem clip. Then export it in a different format (eg Magix video) then delete the problem clip from your project and import this new clip in its place.

Hope this helps.