I'm not sure what desktop configuration you are using (xfce, kde, gnome, etc.). You probably need to review the .vnc/xstartup file and ensure you have the correct configuration for the respective desktop you are using (or try removing and re-installing tightvncserver).
The missing hostname problem is another issue altogether. Not sure what you may have going on there but you may want to consider deleting that EC2 instance and start over with a new one. Ensure the 1st thing you do after bringing up the instance is to install the kali metapackage:
Code:
apt-get update
apt-get install kali-linux-full
Then install X and your desktop (below would be for xfce):
Code:
apt-get install xorg xfce4 xfce4-places-plugin xfce4-goodies
Check to see if tightvncserver is installed:
Code:
dpkg --get-selections |grep tightvncserver
If package is missing:
Code:
apt-get install tightvncserver
Start vncserver (it will ask you to set the password):
Stop vncserver
Edit .vnc/xstartup based on your X desktop (below is for xfce):
Code:
#!/bin/sh
xrdb $HOME/.Xresources
xsetroot -solid grey
#x-terminal-emulator -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
#x-window-manager &
# Fix to make GNOME work
export XKL_XMODMAP_DISABLE=1
#/etc/X11/Xsession
/usr/bin/xfce4-session
Hope this helps...