I installed it using the Update System Panel also. It created the directories /opt/webshare and /opt/webshare-tools. It also puts a new Panel in Server-Manager called "Web Shares" under the Collaboration heading.
You use the Web Shares panel to create a new wedshare. Creating a new webshare called "music" makes a new directory /opt/webshare/music. You can then add and control users from the server-manager panel. Files are stored in the /opt webshare/music directory.You can then use it via
https://yourdomain.com/webshare/music. Note that it is https not http.
That is how it works for me with SME 5.1.2.
If the installation did not create the directories then you should try uninstalling and then do a new install. Be sure to install perl-Apache-Htpasswd-1.3-10.i386.rpm first then install devinfo-mitel-webshare-0.0.1-3.noarch.rpm. If that still does not work you will need to contact Darrell May, his email address is in the README.txt file, for some assistance.
Bob