OK. The Problem was:

I must purge the usrmerge Packet (remove or reinstall is not enough!) and than install usrmerge. And I had to manually set the Link from /sbin/udevadm to /bin/udevadm.

Thanks for you Help.

I have found a Workaround:

in the Directory /usr/share/initramfs-tools/hooks add a Script with follow Content:

#!/bin/sh

  PREREQ=""

  prereqs()
  {
          echo "$PREREQ"
  }

  case $1 in
  # get pre-requisites
  prereqs)
          prereqs
          exit 0
          ;;
  esac

  . /usr/share/initramfs-tools/hook-functions
  cp -pnL /lib/x86_64-linux-gnu/libacl.so.1 ${DESTDIR}/lib/x86_64-linux-gnu/

and this Solve the Problem. But, Why the Default Hooks and Scripts of initramfs Programs not copy the libacl.so.1 to the initramfs?