Hello again.

Thank you all for your very helpful replies  (below)

Here is the error I got when I tried to run my script :

Could not find module `Graphics.GD'

Locations searched:

Graphics/GD.hs

Graphics/GD.lhs

As with the previous errors, I went on Google, to find out which module and/or package I needed to install.

Apparently, I need something called "GD"

When I tried :   cabal install gd

I got the following :

Resolving dependencies...

Configuring gd-3000.7.3...

cabal-1.16.0.2: Missing dependencies on foreign libraries:

* Missing (or bad) header file: gd.h

* Missing C libraries: gd, expat

Failed to install gd-3000.7.3

cabal-1.16.0.2: Error: some packages failed to install:

gd-3000.7.3 failed during the configure step.  The exception was: ExitFailure 1

Upon further inquiries via google,  I found somewhere the following :

This problem can usually be solved by installing the system packages that

provide these libraries (you may need the "-dev" versions). If the libraries

are already installed but in a non-standard location then you can use the

flags --extra-include-dirs= and --extra-lib-dirs= to specify where they are.

I thought I did this already.  

But, apparently, I did something wrong??