At the risk of counting ones chickens before they have hatched I believe I may have fixed the login problem that I was having before
In the administration for the module that controls the login there is a URL redirect section that tells the module where to send users once they have logged in. If this field is left blank it should return users to the front page after login.
I changed this field just adding a forward slash / and it appears to be working.
If you still have login issues please let me know.