Kmulraney

Hi I have just bought the "Linux Format Special edition" exclusive to WH Smith with the 5 CDs which is sopposed to be all I need to install Fedora 5 along side windows XP. I got as far as step 3 then it went straight to step 5. When I chose the "use free space" option I get an error message about partitioning. I'm currently using windows XP on a pentium 3 processor. I have 80 GB hard drive. Can anyone tell me how to overcome this problem? thanks Kev