Try this for your exam-lab (and for any other software that throws such wierd errors on window$$$ 7) :
right-click your program>properties>compatibility TAB>CHECK THE BOX "run this program as an administrator">ok.
Now run setup.
The above can be done for some programs that instal without problems but give odd errors when you run them eg
Tomcat.
HTH
rb
PS :
To the moderators - please add these steps to tomcat, exam-lab etc help pages.