problem switching from stable to testing...

[jpugh@cs.uoregon.edu (enantiomer)]

I have recently made the switch over to debian (woo hoo!) and am
definitely a newbie.  I noticed that when using the apt utilities like
apt-get and apt-cache, much of the software that I want just isn't
available in stable (stable worked fine though).  so i moved over to
testing but couldn't get it to work.  here are the steps that I
took...
1.  first used apt-spy to get a list of testing servers 'apt-spy -d
testing'
2.  then tried 'apt-cache search firebird'
but it didn't work it kept on giving me a "Couldn't stat source
package list ftp://mirrors.usc.edu TESTING/contrib Packages
(/var/lib/apt/lists/mirrors.usc.edu_pub_linux_distructions_debian_dists_TESTING_contrib_binary_i386_Packages)
- stat (2 No such file or directory)"
error type of message for each testing source in my sources.list file

i then tried running 'apt-get update' and got the same error.  why
does this process work under stable but not testing?  I have scoured
the google groups site trying to figure this out and have read close
to a hundred articles probably and would really appreciate some help. 
Anyone?  Thanks!
   Enantiomer