When the login is resulting in the homepage for the Thon to reload, it is usually the result of the supporter trying to login with a username and password that is not registered with the event.

For example:
In 2010, Supporter X registered for your event, and setup a username and password. The system will create a contact record for the supporter. (Contact Record 1)
In 2011, Supporter X registered for your event, but had moved since 2010. Thus, their address was different. As a result, the system will create a new Contact Record for the supporter, rather than updating the existing record. (Contact Record 2)

This results in Supporter X having two seperate contact records (Contact Record 1 and 2). Contact Record 1 is registered with the 2010 event, but not the 2011 Event, and vice versa.

If the Supporter attempts to login to the 2011 event using the 2010 login info, it will redirect them to the homepage of the event, as the login info is incorrect for the 2011 event.

In order to resolve this, you have to determine first if the supporter is registered for the event they are trying to log in to. To do so:

1) Go to Bookkeeping for the event
2) Click Manage Intiative Records
3) Search for the Participant

If they show up in the list, the record you are seeing here is the one that is registered. Click the last name to open the Contact Record, and send them their login info from the "Profile" tab.

If they are not registered, either the Supporter, or you, will need to register the supporter for the event.