the system drive you are working with doesn't have the samples loaded properly. Reinstall them from the discs that come with Logic, into the default place (usually in the main Library/application support/Logic/ samples folder...
Sometimes you have to do it twice. Also, only select the samples, and don't load the effects or source music... they are a waste of space. The main important user library is about 13 GB of samples, and don't forget to select the apple loop libraries.
A word of advice: look for older threads in the LUG, you will often find your answers there (in fact there was a thread a few weeks ago that covered BOTH the questions you asked today). Take the time to learn up about Logic on your own.. asking simple questions shows a lack of effort on your part to learn the basics of Logic or DAWs in general... Most people will ignore you, or worse, flame you....
Peachpit, Groove 3, Mac Pro Video, go to Amazon and enter "Logic Pro" and you will come up with a list of great books and videos about Logic.
So, to summarize: Look for past emails that ask the same question before you post your. Chances are they have already been asked a number of times, and 2) get a book, watch a video, whatever you need, so you get an idea of the basics of Logic... then you won't have to ask what most consider a foolish question (yes, I'm being kind), ok.