Project build failing due to package restore not being enabled in dev box is one of the common scenarios.
The build error that is shown in this case says how to enable it from UI. But there are cases where it fails on a build machine.
Example :
http://stackoverflow.com/questions/14438650/include-nuget-packages-in-teamcity
It would good to update the error message to have a mention about setting "EnablePackageRestore" via config file or env variable. Or provide a help link which points to our docs.