I think the problem is that it has no Erubis support. It says:
But I use Erubis. I provide the path to Ruby bin/ directory:5. Enter the path to eruby.exe file (a part of eRuby interpreter)
C:\RailsInstaller\Ruby1.9.3\bin
and there are two interpreters in it to run: erb.bat and erubis.bat. None of them is started because I do not see a parsed page when I click "Preview". I tried to provide exactly the path to the file of erubis.bat:
C:\RailsInstaller\Ruby1.9.3\bin\erubis.bat
and when I click "Preview" that hangs up Webuilder.
Is there a way to use Erubis in Webuilder? How?