Can't install Mavericks on Fusion 6 (can't change partition table)

When installing mavericks I cannot choose the vmware hard drive because it tells me it is not partitioned using the GUID partition table. 

I then follow the instructions to change this by using the disk utitlity. The instructions do not work.

I get an error telling me the disk cannot be unmounted.

How do you install Mavericks in vmware fusion 6 without this error?

Thanks