problems with apt

[Svante Signell <svante.signell@telia.com>]

Recently apt stopped working:
E: Dynamic MMap ran out of room. Please increase the size of
APT::Cache-Limit. Current value: 25165824. (man 5 apt.conf)
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 libextlib-ruby-doc (NewFileDesc1)
E: Problem with
MergeList /var/lib/apt/lists/ftp.se.debian.org_debian_dists_sid_main_i18n_Translation-en
E: The package lists or status file could not be parsed or opened.

Whatever I do to set the cache-limit, apt thinks the size is: 25165824

I'm using apt-0.8.15.9 and 0.9.2-b1 for the rest, and it worked until
very recenly. 0.9.3 still has the rred segfault problem, and 0.9.4 seems
to FTBFS (from trhe buildds). What to do?