@klaus21 - I know Peter is away on vacation for a couple of weeks...I am NOT a Multi-PE expert, but will have a look at the log file...
It looks like you are on a Hard Drive, and that you have made a copy of the source DVD and that you have the WAIK installed, and it could the right tools/drivers for an SP1 source.
SetVar - Sucessfuly changed the value of [%WimBootID%] to: [EnO2B2de0617601]
SetVar - Sucessfuly changed the value of [%WimInstallID%] to: [EnO2I1de0617601]
These lines in the script say that it found the boot image (#2) and the install image of #1, and I think the "de" means a german language DVD source...So far - so good...a little bit later, I see
IF - Directory exists: [%BaseDir%\Workbench\multiPE_Win7\StoredWims\EnO2B2de0617601] evaluated string: [If,Not,EXISTDIR,%MountDir%\%WimBootID%,DirMake,%MountDir%\%WimBootID%][/color]
As an "ignored" line, which is also OK, since it means that the directory exists so it doesn't need to create it again...But you should check this area to make sure that it really extracted the files into it OK (maybe in a previous run?) because the error that halts the build is that it can't find a file it wants to copy (StoredWims\EnO2I1de0617601\Windows\System32\de-DE\shell32.dll.mu_).
I would go into the "StoredWims" directory and just clean it out, and let the project re-extract the files...
If that works - great - if not, then we have more detective work to try...