Information I've found here suggests that for my system, I need to install 13.04 into an EFI-type partition, since it needs to boot as UEFI. I also understand it is advisable to have only ONE EFI partition on the disk; I've read here that it is OK for Ubuntu and Windows to share the same partition (please confirm). When I try to install into the existing EFI drive, I get the message "No root file system is defined. Please correct from partitioning menu." Do I change the EFI boot partition to another type? Doesn't that defeat the purpose? If I change it to Ext4 Journaling File System, I am given the opportunity to define the '/' Mount point. I haven't proceeded beyond this point for fear I am going to destroy Windows 8 by altering this partition.

BTW, I created three partitions in Windows before installing, per the helpful response to my previous question. But if I try to install into the partition I created for Ubuntu, I get the "No root file system..." error again.