Creating a Dual Boot using Fedora 11 - could not create partition
 

I am making several computers dual boot (Windows XP & Fedora 11). All of the computers already have a Windows XP partition. Most of these systems utilize about 1/2 of the hard drive and have the extra disk space for the Fedora 11 installation. I have installed Fedora 11 on these systems without any problems. However, a few of the systems only have a single Windows partition utilizing the entire hard drive. There is plenty of free space on these drives, but when installing Fedora 11 on these systems, I get part way into the install about partitioning, and the following error pops up "fedora 11 partitioning - could not create partition : not enough free space available ". Is this error caused by the single Windows XP partition? Can Fedora 11 re-partition the single Windows XP partition allowing a Windows XP partition and a Fedora 11 partition? Or do I have Windows make a single smaller partition allowing the extra space for the Fedora 11 installation? Or is there some other magic out there I should know about? Thanks for any help.
Cubsman

My suggestion for those systems where windows use the entire drive .
Defrag the windows drive.
shrink the windows partition
Use gparted to create /ext3
/ ext 4
swap

AND of course start with making a backup first