Which vsphere version are you using?

I've cut&pasted this script 1:1 and again the following error:

SOAP Fault:

-----------

Fault string: Ein angegebener Parameter war nicht korrekt.

spec.sharesInfo.limit

Fault detail: InvalidArgument

My script worked with vsphere 5.1, but with 5.5 (U2 or above) it doesn't - maybe you have 5.1?