not sure what this error message means.
 

Im trying to install redhat, I already have XP on this system. In the installation I get to the screen that asks were i want to instal. I want to keep XP so I want to put linux in the unused space. when i click that option i get this message.

Partitioning Failed: Coule not allocate partition as primary partitions.

If your system already has partitions, and there are four primary partitions this is your problem. A HD can only have four primary partitions.

Also there are problems resizing NTFS partitions and the installer maynot be able to do this for you.