apt-get: mixed system

[Luis R Finotti <finotti@math.ucsb.edu>]

Dear all,

I am trying to install a program (gphoto2) from the testing distribution
in my stable system.  I tried to follow the instructions on 

http://www.debian.org/doc/manuals/apt-howto/ch-apt-get#s-default-version

First I noticed that I did not have a "/etc/apt/apt.conf" file.  So I
created one with (only) the line

APT::Default-Release "stable";

(I _did_ have a "/etc/apt/apt.conf.d" directory with a "70debconf" file in
it.  I also tried adding the above line to "70debconf" and putting the
"/etc/apt/apt.conf" file in the "/etc/apt/apt.conf.d" directory.)

Here is my "/etc/apt/source.list" file:

-----------------------------------
deb http://http.us.debian.org/debian stable main contrib non-free
deb http://non-us.debian.org/debian-non-US stable/non-US main contrib
non-free
deb http://security.debian.org stable/updates main contrib non-free

#########################################################################

# this was added to be able to get packages from testing
deb http://http.us.debian.org/debian testing main contrib non-free
-----------------------------------

When I run "apt-get update" I get the following error message:

(...)
Get:8 http://http.us.debian.org testing/non-free Release [85B]                 
Fetched 3142kB in 20s (153kB/s)                                                
Reading Package Lists... Error!
E: Dynamic MMap ran out of room
E: Error occured while processing quagga (NewVersion1)
E: Problem with MergeList
/var/lib/apt/lists/http.us.debian.org_debian_dists_testing_main_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.

Of course, I get the same error if I try "apt-get -t testing install
gphoto2".

Any help would be greatly appreciated!

Thanks and my best to all,

Luis