If you have problems with any of the topics listed then have a look at the previous discussion forums - especially the 2007 forum
http://osprey.unisa.ac.za/phorum/list.php?193 (8 pages) and the 2006 forum
http://osprey.unisa.ac.za/phorum/list.php?10 (3 pages) - it is fairly certain that the problem would have been solved before
Remember that there is another set of exercises (i.e. additional to the Masterskill lessons) for HTML, CSS and JavaScript on your CD in the downloads folder.
Look for the files javascripttutor.zip, cssprimer.zip, and webtutor.zip. Unzip them and start the lessons by opening the index.htm(l) file
You should do these exercises first if you find that you battle with the Masterskill exercises - for the CSS and JavaScript sections these introductory exercises are sufficient for exam purposes.
You can look here for older but still useful additional material:
http://cs-cert.unisa.ac.za/internet/webdesign/index.htm
such as the two Javascript resources
http://cs-cert.unisa.ac.za/internet/resources/netscapedocs/guide/contents.htm, the Web Design primer
http://cs-cert.unisa.ac.za/internet/resources/webdesign/index.htm and the HTML primer
http://cs-cert.unisa.ac.za/internet/resources/html1/barebone.html and
http://cs-cert.unisa.ac.za/internet/resources/yale/contents.html and the Graphics primer
http://cs-cert.unisa.ac.za/internet/resources/webgraphics101/webgraphics101.html