unsolvable problem? ubuntu 12.4

[Krüg Bernd]

E: Encountered a section with no Package: header
E: Problem with MergeList 
/var/lib/apt/lists/de.archive.ubuntu.com_ubuntu_dists_precise-updates_main_binary-i386_Packages
E: The package lists or status file could not be parsed or opened


Paketinformationen konnten nicht initialisiert werden

Ein unlösbares Problem ist während der Initialisierung der 
Paketinformation aufgetreten.

Bitte melden Sie einen Fehler im Paket »update-manager« und fügen Sie 
die folgende Fehlermeldung an den Fehlerbericht an:

'W:Duplicate sources.list entry cdrom://Ubuntu 12.04 LTS _Precise 
Pangolin_ - Release amd64 (20120423)/ precise/main i386 Packages 
(/var/lib/apt/lists/Ubuntu%2012.04%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20120423)_dists_precise_main_binary-i386_Packages), 
W:Duplicate sources.list entry cdrom://Ubuntu 12.04 LTS _Precise 
Pangolin_ - Release amd64 (20120423)/ precise/restricted i386 Packages 
(/var/lib/apt/lists/Ubuntu%2012.04%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20120423)_dists_precise_restricted_binary-i386_Packages), 
W:Duplicate sources.list entry cdrom://Ubuntu 12.04 LTS _Precise 
Pangolin_ - Release amd64 (20120423)/ precise/main i386 Packages 
(/var/lib/apt/lists/Ubuntu%2012.04%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20120423)_dists_precise_main_binary-i386_Packages), 
W:Duplicate sources.list entry cdrom://Ubuntu 12.04 LTS _Precise 
Pangolin_ - Release amd64 (20120423)/ precise/restricted i386 Packages 
(/var/lib/apt/lists/Ubuntu%2012.04%20LTS%20%5fPrecise%20Pangolin%5f%20-%20Release%20amd64%20(20120423)_dists_precise_restricted_binary-i386_Packages), 
E:Encountered a section with no Package: header, E:Problem with 
MergeList 
/var/lib/apt/lists/de.archive.ubuntu.com_ubuntu_dists_precise-updates_main_binary-i386_Packages, 
E:Die Paketliste oder die Statusdatei konnte nicht eingelesen oder 
geöffnet werden.'