The file you need in the command is xyz.vmdk, which is the descriptor file for xyz-flat.vmdk. The xyz-ctk.vmdk file is used for changed block tracking on the ESXi host and is not needed in this case. Since the virtual disk contains more than one volume/partition you will need to specify which partition you wabt to mount by adding e.g. /v:2 to the command line. If this doesn't help, you can use the GUI "Map Virtual Disk" function of VMware Workstation.
André