You just need to make sure that the user has the windows security enabled for that user for that application.
Check by doing this.
Go to QVW file (Physical Location in folder). -> Right Click -> Security -> find the "Users"
If users group is added then you dont need to do anything.
If users group is not there then you will have to add all 100 users in this security.
Once you do this, all users will have access to qlikview application on accesspoint.
What setting is done in web server?
Are they using the alternate login page to login?
You can ask them to try with only username.