If you get the above error while executing a power script, it maybe due to the Execution Policy.
An overview of the policy levels:
Restricted: Individual cmdlets can run, but not saved Powershell scripts. This is the default setting.
AllSigned: Scripts can run, but must have a digital signature even if written on the local computer. Prompts you before running scripts from trusted publishers.
RemoteSigned: Scripts written on the local computer do not need a digital signature, but any script downloaded from outside (email, IM, Internet) must have a signature to execute.
Unrestricted: Any script can run, but scripts downloaded from outside will run with a warning.
If you are a developer and working on powershell, you might want to go for the Un-Restricted option.
