从 ovirt-engine KVM 虚拟机导出 ova 文件后，当我尝试将 ova 文件导入回 Xen 服务器时出现此错误：
2022-01-17 15:51:40,844 INFO XenOvf.OVF [Main program thread] - Started validation of package vm
2022-01-17 15:51:40,846 INFO XenOvf.OVF [Main program thread] - Validating OVF version
2022-01-17 15:51:40,846 WARN XenOvf.OVF [Main program thread] - OVF version not set, assuming 1.0.0
2022-01-17 15:51:40,852 WARN XenOvf.OVF [Main program thread] - Found unexpected virtual hardware type ENGINE 4.1.0.0.
2022-01-17 15:51:40,853 INFO XenOvf.OVF [Main program thread] - Validating CPU
2022-01-17 15:51:40,853 INFO XenOvf.OVF [Main program thread] - CPU has an invalid InstanceID, creating a new one.
2022-01-17 15:51:40,853 INFO XenOvf.OVF [Main program thread] - Validating Capabilities
2022-01-17 15:51:40,854 INFO XenOvf.OVF [Main program thread] - Validating Memory
2022-01-17 15:51:40,854 INFO XenOvf.OVF [Main program thread] - Memory has an invalid InstanceID, creating a new one.
2022-01-17 15:51:40,854 INFO XenOvf.OVF [Main program thread] - Validating Capabilities
2022-01-17 15:51:40,854 INFO XenOvf.OVF [Main program thread] - Validating disks
2022-01-17 15:51:40,855 INFO XenOvf.OVF [Main program thread] - Validating Capabilities
2022-01-17 15:51:40,855 INFO XenOvf.OVF [Main program thread] - Validating Networks
2022-01-17 15:51:40,855 INFO XenOvf.OVF [Main program thread] - Network has an invalid InstanceID, creating a new one.
2022-01-17 15:51:40,855 INFO XenOvf.OVF [Main program thread] - Validating Capabilities
2022-01-17 15:51:40,856 INFO XenOvf.OVF [Main program thread] - Validating Networks
2022-01-17 15:51:40,856 INFO XenOvf.OVF [Main program thread] - Network has an invalid InstanceID, creating a new one.
2022-01-17 15:51:40,856 INFO XenOvf.OVF [Main program thread] - Validating Capabilities
2022-01-17 15:51:40,856 INFO XenOvf.OVF [Main program thread] - Validating Capabilities
2022-01-17 15:51:40,859 FATAL XenAdmin.Program [Main program thread] - Uncaught exception
System.NullReferenceException: Object reference not set to an instance of an object。
XenOvf.OVF.ValidateCapability(RASD_Type rasd, List`1& warnings)
XenOvf.OVF.Validate(Package package, List`1& warnings)
XenAdmin.Wizards.ImportWizard.ImportSourcePage.LoadAppliance(String& error)
XenAdmin.Controls.Common.PasswordFailure.PerformCheck(CheckDelegate[] checks)
XenAdmin.Wizards.ImportWizard.ImportSourcePage.PageLeaveCore(PageLoadedDirection direction, Boolean& cancel)
XenAdmin.Controls.XenTabPage.PageLeave(PageLoadedDirection direction, Boolean& cancel)
XenAdmin.Wizards.XenWizardBase.WizardProgress_LeavingStep(Object sender, WizardProgressEventArgs e)
XenAdmin.Wizards.WizardProgress.OnLeavingStep(Boolean isForwardsTransition)
XenAdmin.Wizards.WizardProgress.NextStep()
XenAdmin.Wizards.XenWizardBase.buttonNext_Click(Object sender, EventArgs e)
System.Windows.Forms.Control.OnClick(EventArgs e)
System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
System.Windows.Forms.Control.WndProc(Message& m)
System.Windows.Forms.ButtonBase.WndProc(Message& m)
System.Windows.Forms.Button.WndProc(Message& m)
System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
我该如何解决上述问题？