what kind of server are you running this on? presuming linux-based since it's asking for htaccess, but apache can run on windows servers too i think.
if its looking for an .htaccess then something with your apache config is borked. make sure there's a proper path to access it, and you can add a file called .htraccess in the webim root directory with whatever rules you need for apache to access it. there's plenty of documentation on htaccess configuration.