Howto prevent certificate error output from the commandline of a powershell script

When I run a powershell script directly from MSDOS that automaticaly logs in I get the following output:

There were one or more problems with the server certificate:

..

* A certification chain processed correctly, but terminated in a root certificat

e which isn't trusted by the trust provider.

...

I don't need this. What to do to prevent this?

MSDOS commandline:

> PowerShell -PSConsoleFile "C:\Progra~1\VMware\Infrastructure\VIToolkitForWindows\vim.psc1" -command c:\vmware_vmfs_status.ps1 servername

This is the start of my powershell script:

param(   $VIServer )

$user = "domain\user01"

$pass = "password"

1. connect to the VC server+