Error adding existing virtual machines after removing CDROM from host system

[chrisg83]

1) When I installed VirtualBox 1.5.2, a DVD drive was attached to my Windows XP host.
2) I created a VM image and attached my host DVD drive to it.
3) I removed the DVD drive from my host system.
4) I moved the VM HDD (vdi image) to another location.
5) I deleted the VM entry in Virtualbox.
6) I want to create a new VM in Virtualbox using that moved .vdi image. When I say finish on the summary page of the virtual machine creation wizard, it says (translated from German): Could not create a new virtual machine. Callee RC: RPC_E_SERVERFAULT (0x80010105). Could not find Host drive F (which was my DVD drive). When I exit VirtualBox application, it crashes.