Errors during "4.8.1 release" build

i am trying to build “4.8.1 release” from source.
but i am having 2 errors on this line:

friend bool ULandscapeInfo::ApplySplinesInternal(bool bOnlySelected, ALandscapeProxy* Landscape);

the line is from:

“Source\Runtime\Landscape\Classes\LandscapeSplinesComponent.h 171”

Errors:

Error 1 error C2653: ‘ULandscapeInfo’
: is not a class or namespace
name Z:\UnrealEngine_X_X_X_release_Build\Engine\Source\Runtime\Landscape\Classes\LandscapeSplinesComponent.h 171
Error 2 error C2061: syntax error :
identifier
‘ALandscapeProxy’ Z:\UnrealEngine_X_X_X_release_Build\Engine\Source\Runtime\Landscape\Classes\LandscapeSplinesComponent.h 171

it turns out that “RollercoasterPlugin” was including “Source\Runtime\Landscape\Classes\LandscapeSplinesComponent.h”

dont know why but it was causing that problem.
removing the plugin solved the issue.