Import-SCStorageProvider Object deleted

Hi

I'm trying to add my Dell EqualLogic PS series storage array into SC VMM SP1 by following the steps outline on this link

http://social.technet.microsoft.com/wiki/contents/articles/12038.vmm-2012-sp1-installing-and-configuring-dell-equallogic-ps-series-smp-provider.aspx

However, every time I run the import-scstorageprovider cmdlet the provider is not added. I've checked the event viewer and the command completes without error. Also in the VMM jobs window I can see the job completed. Interestingly the job window shows"Object deleted" in the result name column.

I'm struggling to figure out where this is going wrong. Can anyone advise?