Could not initialize the package information

An unresolvable problem occurred while initializing the package information.

Please report this bug against the 'update-manager' package and include the following error message:

'E:Dynamic MMap ran out of room. Please increase the size of APT::Cache-Limit. Current value: 25165824. (man 5 apt.conf), E:Error occurred while processing firefox-3.5 (NewVersion2), E:Problem with MergeList /var/lib/dpkg/status, E:The package lists or status file could not be parsed or opened.'