Major Failure after 7.04 upgrade from 6.10

After upgrading for 6.10 (which was working very well) to 7.04... I get the following errors:

When accessing Synaptic manager I get the following message:

E: Dynamic MMap ran out of room
E: Dynamic MMap ran out of room
E: Error occurred while processing libpacklib1-dev (NewVersion1)
E: Problem with MergeList /var/lib/apt/lists/ftp.debian.org_debian_dists_stable_main_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.
E: _cache->open() failed, please report.

When accessing Add/Remove I get the following message:

Failed to check for installed and available applications

This is a major failure of your software management system. Please check for broken packages with synaptic, check the file permissions and correctness of the file '/etc/apt/sources.list' and reload the software information with: 'sudo apt-get update' and 'sudo apt-get install -f'.

I am a MS Windows convert and have very little knowledge of the inner working of any Linux product. Any help would be appreciated, the more "step by step" the better