At the time this video was made in 2004, Flash (.swf) was how videos were provided on the web.
Flash has since become almost obsolete. So the above video is now provided as a WEBM.
The original Flash video can still be found here.
This video is old; some things have changed since it was made:
At the time this video was made in 2004, FLTK 1.1.x was the latest version,
which is now VERY OLD. Don't use that, use the latest version of FLTK on the website.
The fltk.org website changed;
To download the fltk source code, you now have to go to the
FLTK LIBRARY | DOWNLOAD section of the fltk.org website.
In version fltk 1.3.x, the "fltk.dsw" was moved to "ide/VisualC6/fltk.dsw". In older releases (fltk 1.1.10 and back), it was in "visualc/fltk.dsw".
When setting up your own app, there are likely different windows libraries
that need to be included under the Linker > Command Line > Additional options
since this video was made. Try building one of the FLTK test programs most like
your app without making changes to this field. If it works, no changes are needed.
If it doesn't work, look at the build log for the FLTK hello demo to see what libs
it used to build, and updating this setting accordingly to add any missing libs.
Or, look at the linker settings for the test program, and set your app up similarly.