The class adodb-xmlschema.inc.php included in the .zip files is not compatible with PHP 7.1. If you are able to find and edit the file to replace all of the code in that file with all of the code presented here…ADOdb/adodb-xmlschema.inc.php at master · ADOdb/ADOdb · GitHub, it should work. I deleted the contents of adodb-xmlschema.inc.php, then copied and pasted this code in, saved the file, refreshed the page at step 4, and it continued with a successful install. Good luck!