The "Unexpected error in initialization phase:" should be followed by the actual error message.
Do you see anything after that line?

The previous message, "No com.lightstreamer.kernel_lib_path defined; using a unique ClassLoader; ignoring any other _lib_path supplied", is not an error.
It can be issued if you launch the Server directly, without using the factory scripts and without passing the needed JVM properties, but this does not prevent the Server from starting.
However, if there is something missing or wrong in the classpath supplied to the JVM, this may explain the startup failure.
But to understand what's wrong we need either to see the full log, or to see exactly the command you used to launch the JVM.