LucD,
I ams till getting the error
Here is modified PowerCLI SCript:
Import-Csv "C:\Users\sg0217865\Desktop\NewVMs.csv" -UseCulture | %{
Get-OSCustomizationSpec $_.Customization | Get-OSCustomizationNicMapping | Set-OSCustomizationNicMapping -IpMode UseStaticIP -IpAddress $_.ip
-SubnetMask $_.subnet -DefaultGateway $_.gw
$vm=New-VM -Name $_.Name -Template $_.Template -Host $_.Host -Datastore $_.Datastore -Confirm:$false -RunAsync -OSCustomizationSpec
$_.Customization
}