Is a program saying this? Is the OS saying this? You say your using 10.2, thats a very VERY old version of OS X. Which OS are you using? You say Leopard and Snow Leopard? You need to provide more details. What computer, specs, hard drive size, what apps are you running, when does this error message pop up etc etc.
If you are neutral in situations of injustice, you have chosen the side of the oppressor. If an elephant has its foot on the tail of a mouse and you say that you are neutral, the mouse will not appreciate your neutrality. Bishop Desmond Tutu