I have a 60 gig hard drive with two partions 30 gig each. first one with winxp pro. fedora core will boot but win I get to the partition part it says, could not allocate requested partition

partitioning failed:could not allocate partitions as primary partitions

select to make logical partition in the exntended partitions.

Just to expand a bit on what shams told you...

you can only have four primary partitions on a HDD. However it is possible to make an extended partition which can contain a larger number of partitions. That means that one of your primary partitions is labeled 'extended and inside that partition you can create logical partitions. If you try to make a primary partition inside an extended partition you will get an allocation error mesage.

Since there can be a maximum of four primary partitions (named in linux as devices hda1 to hda4) the first logical partition will be named hda5, even if not all of the four primary partitions actually exist. (not really what you asked, but I got a bit carried away.)