Unable to install virtual box guest additions on Lubuntu 16.04

I am unable to install virtual box guest additions in Lubuntu 16.04

My following is my terminal screenshot:

enter image description here

When I type in terminal ./autorun.sh

I get the following output:

Linux guest additions installer not found --try to start them manually.

Why this is happening and how to "start them manually"?

I have tried shutting down the machine, removing guestadditions.iso, restarting the machine, and reinserting the guest additions CD.

But the problem persists.

Why is this happening?

Solution 1:

I managed to solve my problem, it is pretty easy.

What I did was I opened terminal and typed:

apt update
apt upgrade #To install Linux headers
apt install gcc
apt install make
cd /media/"username"/VBOX*
./VBoxLinuxAdditions.run
reboot

Then I set the monitor screen resolution to mine (which is 1360x644)

Then I restarted it again.

And it is done