RHEL 6 fails to load install.img during PXE boot

I am trying to load RHEL using PXE boot over the network. I am able to install RHEL 7.2 successfully. However, with both 6.4 and 6.6 I run into the following issue. The kernal and initrd are loaded succesfully, and then the product.img is loaded. When it goes to load the install.img file, it always hangs up along the way.