Dynamic MMap ran out of room when trying to sudo apt-get anything

I was having an error in Update Manager that asks me to do a partial upgrade and it fails. Now I can't sudo apt-get install anything. I tried to fix it, and now I can't sudo apt-get anything. Every time, I get this output:

Reading package lists... Error!
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 libuptimed0 (NewVersion1)
E: Problem with MergeList
/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid_universe_binary-i386_Packages
W: Unable to munmap
E: The package lists or status file could not be parsed or opened.

I have no idea why this is happening or how to fix it, and I fear that if I try something that probably doesn't work that it will make my problem worse. (Just for reference I am currently running 10.04 (Lucid) on my machine.)

I believe one solution is just increase the value APT::Cache-Limit at the /etc/apt/apt.conf.d/70debconf, to do so use:

sudo gedit /etc/apt/apt.conf.d/70debconf

and add the following to the end of the file:

APT::Cache-Limit "100000000";

..and then run:

sudo apt-get clean
sudo apt-get update --fix-missing