I know many people have had a hard time with this particular kit. I REALLY did! This is how I managed to get mine to finally work.
Here is the kit I am speaking of. http://www.radioshack.com/make-it-robotics-starter-kit/2770168.html#.VIvKBjHF-g4
These are the support files you will need. http://blog.radioshack.com/wp-content/uploads/2014/05/Make-it-Robotics-Starter-Kit-Support-Files.zip
The YouTube Video I used to learn how to add a Library to Arduino IDE. https://www.youtube.com/watch?v=fsMg6F6yYlo
Once you have completed this go into your Arduino IDE and do the following. (Your Arduino Uno R3 should be connected to your computer at this point. Ensure you have the current drivers for your Uno R3.) http://arduino.cc/en/guide/windows#toc4
Click "File", then mouse over libraries > Make-It-Robotics-starter-kit-support-Files > Examples > 2770168starter kit > linefollow. Click line follow and Varify then compile. You're welcome.