Strange terminal output after every installation

Hello. I don't fully understand this terminal output so forgive the naive explanation of my problem. Every time I install something via terminal I get this output (I installed sl to produce the output:

Code:

Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: memtest86+ syslinux-themes-debian syslinux-themes-debian-wheezy Use 'apt-get autoremove' to remove them. The following NEW packages will be installed: sl 0 upgraded, 1 newly installed, 0 to remove and 2 not upgraded. 2 not fully installed or removed. Need to get 26.1 kB of archives. After this operation, 117 kB of additional disk space will be used. Get:1 http://http.kali.org/ /kali/main sl i386 3.03-17 [26.1 kB] Fetched 26.1 kB in 1s (14.2 kB/s) Selecting previously unselected package sl. (Reading database ... 358476 files and directories currently installed.) Unpacking sl (from .../archives/sl_3.03-17_i386.deb) ... Processing triggers for man-db ... Setting up linux-image-3.14-kali1-686-pae (3.14.5-1kali2) ... /etc/kernel/postinst.d/initramfs-tools: update-initramfs: Generating /boot/initrd.img-3.14-kali1-686-pae /etc/kernel/postinst.d/zz-extlinux: P: Checking for EXTLINUX directory... found. /boot/vmlinuz-3.14-kali1-686-pae P: Writing config for /boot/vmlinuz-3.14-kali1-686-pae... I: os-proper disabled in /etc/default/extlinux: Skipping /boot/extlinux/os-proper.cfg E: /usr/share/EXTLINUX/themes/debian: No such file or directory run-parts: /etc/kernel/postinst.d/zz-extlinux exited with return code 1 Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-3.14-kali1-686-pae.postinst line 591, <STDIN> line 2. dpkg: error processing linux-image-3.14-kali1-686-pae (--configure): subprocess installed post-installation script returned error exit status 2 Setting up extlinux (3:6.03~pre1+dfsg-1kali3) ... P: Checking for EXTLINUX directory... found. /boot/vmlinuz-3.14-kali1-686-pae P: Writing config for /boot/vmlinuz-3.14-kali1-686-pae... I: os-proper disabled in /etc/default/extlinux: Skipping /boot/extlinux/os-proper.cfg E: /usr/share/EXTLINUX/themes/debian: No such file or directory dpkg: error processing extlinux (--configure): subprocess installed post-installation script returned error exit status 1 Setting up sl (3.03-17) ... Errors were encountered while processing: linux-image-3.14-kali1-686-pae extlinux E: Sub-process /usr/bin/dpkg returned an error code (1)

After searching about this issue the only other suggestion I found for fixing it were

Code:

sudo apt-get install -f

and

Code:

sudo dpkg --configure -a

. Neither of these helped. What is my OS trying to do exactly and why is dpkg returning an error? How do I stop it trying to do what it's doing or stop the error occurring?

Any and all help is greatly appreciated.