Driveimage XML : unable to retrieve drive layout

To create a second primary disk, you'll need to use a partitioning tool to hide the first primary disk. After the second installation, you can then unhide the first one.

Rather than play this game of hiding and unhiding partitions, it's best to use a boot manager to take care of the whole thing. Some such products are :

BootIt NG ($34.95)
Support of over 200 primary partitions (if desired). I've used it and it's probably the best.

GAG (initials, in spanish, of Graphical Boot Manager) (open-source)
Allows boot of up to 9 different operating systems installed in primary and extended partitions. Never used it.

Partition Commander 11 ($49.95)
No info on maximum partitions number. I've used it a long time ago and it worked then pretty well.

Norton PartitionMagic 8.0 ($69.95)
Otherwise called BootMagic, no info on maximum partitions number, and seems to only support partitions up to 300GB. Never used it, and I usually stay away from Norton products.

Warning: Before playing with partitions, take great care with your backups.

It looks like something has trashed your GPT data -- both the main data structures and the backup data structures. I don't know specifically what might have done this, but a buggy partitioning tool seems like the most likely culprit. Another possibility is that there's been some confusion over something like a RAID configuration -- if the disk was originally prepared with your motherboard's RAID features active and then accessed with the RAID features inactive, something like this might have happened.

Two options seem most reasonable at this point:

1. Re-create your partition "blind." The vast majority of modern partitioning tools begin partitions at sector 2048, so you could use gdisk to create a partition that begins at that point and that ends at the last possible sector. This stands a good chance of succeeding, but there's a risk that if your original partition did not start at sector 2048, you could end up damaging it when you try to access the new partition. Also, some tools will try to create a new filesystem when you create a new partition, so using them would be risky at best. (I recommended gdisk for this task because it does not touch the partitions' contents, just the partition table that defines them.) Also, if the disk held an EFI System Partition in addition to the main data partition, the main data partition would not begin at sector 2048.
2. Use a tool like TestDisk (included on many Linux emergency systems, such as PartedMagic and System Rescue CD) to search for your missing partition. (There are Windows equivalents to TestDisk, but I don't know what they are, offhand. You could do a Web search to find them, if you prefer to work from Windows rather than boot a Linux emergency disc.) This will be more likely to find your partition if it was placed strangely, but tools like this can become confused if the disk has been re-partitioned in the past -- they can sometimes detect the remnants of deleted partitions and try to re-create them even though they're no longer valid.

Take your pick as to the approach, and good luck! Whatever you do, though, be cautious. You might consider doing a raw disk backup to a spare disk, if you've got one that's big enough to hold all your data. If you do this, though, be very careful in specifying the source and destination disks, or your backup could end up trashing the data you intend to save!