Windows Server 2012 R2 Essentials Preview has some known issues with Lights-Out 1.5.4 Build 2055 (official release).
Most issues and incompatibilities have been identified and fixed in beta build 2080:
http://www.homeserversoftware.com/lo/whs2011/beta/LightsOutVail1.5.4.2080.wssx
If you evaluate Windows Server 2012 R2 Essentials Preview with Lights-Out, then please uninstall build 2055 and update to build 2080.
There is currently one known issue which requires some additional work for localised builds of Windows Server 2012 R2 Essentials Preview. The Dashboard binaries are no longer stored under C:\Program Files\Windows Server\Bin\, now C:\Windows\System32\Essentials\ is used. This change affects the loading of localised satellite assemblies and as a result, Lights-Out is always displayed in English. Microsoft will fix this issue in RTM.
For the time being, please copy your languages files, for example on a German system copy C:\Windows\System32\Essentials\de to C:\Windows\System32\Essentials\de, on a French system copy C:\Windows\System32\Essentials\fr to C:\Windows\System32\Essentials\fr.