If you got the error message from MS CRM 4.0 which is running on a VM on your test or production Hyper-V manager server, After i checked the the error message on the server, the error message which was :
"'AntiXssLibrary' or one of its dependencies. There is not enough space on the disk. (Exception from HRESULT: 0x80070070)"
Just trun off your VM, Then expand desk space allocated for the VM will fix the issue.
Hope this tip helps.