“Notice: Undefined index: step in… “

I am trying to install WordPress.
install-wp shows the following error message:
Notice: Undefined index: step in E:\webs\monkeysandrobots.com\wwwroot\wordpress\wp-admin\wp-install.php on line 7
I am able to go through the rest of the steps, including Step 3, which displays the following error message:
Notice: Undefined variable: admin_email in E:\webs\monkeysandrobots.com\wwwroot\wordpress\wp-admin\wp-install.php on line 713
When I try to login, similar error messages are shown, and I am unable to log in. What could be wrong?
I haven’t edited any file, except for wb_config, and I only entered in databse name, user name, and password.