Could not add DVD drive to machine DC1

I'm getting three errors during the deployment. Maybe one error has to do with the other.

This is the first error I get.

12:15:48|00:00:07|00:00:00.000| Lab 's4bhomeLab' hosted on 'HyperV' imported with 10 machines
Get-ItemPropertyValue : Property ServerNano does not exist at path HKEY_LOCAL_MACHINE\software\Microsoft\Windows NT\CurrentVersion\Server\ServerLevels.
At C:\Program Files\WindowsPowerShell\Modules\AutomatedLabNotifications\Private\Send-ALToastNotification.ps1:16 char:25
+ ... oreOrNano = Get-ItemPropertyValue 'HKLM:\software\Microsoft\Windows N ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Get-ItemPropertyValue], PSArgumentException
+ FullyQualifiedErrorId : Argument,Microsoft.PowerShell.Commands.GetItemPropertyValueCommand

This is the second error: I get this error 10 times, one for each host.

12:15:54|00:00:06|00:00:01.659| - The hosts file has been added 10 records. Clean them up using 'Remove-Lab' or manually if needed
12:15:54|00:00:06|00:00:00.000| - Creating HyperV machine 's4bfe01'..Set-VMFirmware : A parameter cannot be found that matches parameter name 'SecureBootTemplate'.
At C:\Program Files\WindowsPowerShell\Modules\AutomatedLabWorker\AutomatedLabWorkerVirtualMachines.psm1:296 char:52
+ ... vm | Set-VMFirmware -EnableSecureBoot Off -SecureBootTemplate Microso ...
--------------------------------------------------------------------------------------------------
This is the third error: It just sits there retrying to mount the iso file for the domain controler

12:24:50|00:09:02|00:00:00.000| Installing Certificate Servers
12:24:50|00:09:02|00:00:00.000| - Machines with Root CA role to be installed: 'DC1'
12:24:50|00:09:02|00:00:00.000| - Waiting for machines to start upCould not add DVD drive 'D:\LabSources\ISOs\en_windows_server_2012_r2_x64_dvd_2707946.iso' to machine 'DC1'. Retry
ing.
12:25:03|00:09:14|00:00:12.543| - Could not add DVD drive 'D:\LabSources\ISOs\en_windows_server_2012_r2_x64_dvd_2707946.iso' to machine 'DC1'. Retrying.
12:25:08|00:09:19|00:00:17.546| - Could not add DVD drive 'D:\LabSources\ISOs\en_windows_server_2012_r2_x64_dvd_2707946.iso' to machine 'DC1'. Retrying.
12:25:13|00:09:24|00:00:22.556| - Could not add DVD drive 'D:\LabSources\ISOs\en_windows_server_2012_r2_x64_dvd_2707946.iso' to machine 'DC1'. Retrying.
12:25:18|00:09:29|00:00:27.564| - Could not add DVD drive 'D:\LabSources\ISOs\en_windows_server_2012_r2_x64_dvd_2707946.iso' to machine 'DC1'. Retrying.
12:25:23|00:09:35|00:00:32.579| - Could not add DVD drive 'D:\LabSources\ISOs\en_windows_server_2012_r2_x64_dvd_2707946.iso' to machine 'DC1'. Retrying.

My host machine is windows 2012r2 with hyper-v
This is the output of the deployment process
[s4bDeployment.txt](https://github.com/AutomatedLab/SfBAutomatedLab/files/1589407/s4bDeployment.txt)

I have the feeling that I'm missing something very small, but I can't really figure it out yet after days now. I hope somebody knows what is going on.
Thank you in advance.