Hi Matthias,
maybe you haven´t recognized it, but this forum is in english language, in that reason it would be good to write in english instead of german, otherwise you might not expect to get an answer.
now to your “general error” in encore. first of all you haven´t told us which version of encore you´re using.
we all know, there are several short-commings within encore that could result in errors. to probably prevent them you should try this:
1. encode all assets prior authoring to m2v and ac3 dolby digital.
2. DONT use any h264-quicktime- or mp4-files for authoring (or editing), don´t use dynamic linking from premiere pro to encore.
3. start a new project from scratch and use previously encoded video- and audio-files.
good luck….
danny