Hi Marianne. If you have cPanel or FTP access to your site, first thing to try is going to the /wp-content/plugins folder and rename the /wpml-all-import folder to something else to disable the plugin. Then see if you can access your site. If not, try renaming the /plugins folder to something else to disable all the plugins, then try to access your site. There may be something else going on as well because this part of your URL “/p3pnexwpnas07_data03/78/2833078/” doesn’t look normal. Also found this report of the same error from a couple of weeks ago on the WPML.org support site:
https://wpml.org/forums/topic/fatal-errorclasspmxi_pluginnot-found-error-code-for-all-import-plugin/