FreeBSD 6.3 installation hacked

[Aflatoon Aflatooni]

My server installation of FreeBSD 6.3 is hacked and I am trying to find out how they managed to get into my Apache 2.0.61. 

This is what I see in my http error log:

[Mon Sep 21 02:00:01 2009] [notice] caught SIGTERM, shutting down
[Mon Sep 21 02:00:14 2009] [notice] Apache/2.0.61 (FreeBSD) PHP/5.2.5 mod_jk/1.2.25 configured -- resuming normal operations
wget: not found
Can't open perl script "/tmp/shit.pl": No such file or directory
wget: not found
Can't open perl script "zuo.txt": No such file or directory
curl: not found
Can't open perl script "zuo.txt": No such file or directory
lwp-download: not found
Can't open perl script "zuo.txt": No such file or directory
lynx: not found
Can't open perl script "zuo.txt": No such file or directory
zuo.txt                                                 11 kB   56 kBps
wget: not found
Can't open perl script "/tmp/shit.pl": No such file or directory
wget: not found
Can't open perl script "zuo.txt": No such file or directory
curl: not found
Can't open perl script "zuo.txt": No such file or directory
lwp-download: not found
Can't open perl script "zuo.txt": No such file or directory
lynx: not found
Can't open perl script "zuo.txt": No such file or directory
zuo.txt                                                 11 kB  107 kBps
Died at zuo.txt line 20.
GET: not found
Can't open perl script "zuo.txt": No such file or directory
wget: not found
Can't open perl script "zuo.txt": No such file or directory
curl: not found
Can't open perl script "zuo.txt": No such file or directory
lwp-download: not found
Can't open perl script "zuo.txt": No such file or directory
lynx: not found
Can't open perl script "zuo.txt": No such file or directory
zuo.txt                                                 11 kB  108 kBps
Died at zuo.txt line 20.