That error points to something related to WPML plugin. The Alora theme code detects the presence of WPML plugin’s ICL_LANGUAGE_CODE PHP constant, but encounters error when it tries to do something…
I think you have WPML plugin install and activated.
Please disable all WPML plugins and activate only after you have installed the theme and activated theme.
Hope this solves your issue. You are welcome to get back to me if you still encounter errors.