i don't have a login feature on my forum i do have a register link, so i tried with a new forum theme i downloaded from here but still no luck
Forum themes or possibly "skins" can not related at all to the login's appearance. Register link always should appear at the top menu of all forums, not depending on what kind of skin you have installed. Re-installation shamanism also is not the reason here.
Can not proceed: possible CSRF/XSRF attack!(THAT OCCURS WHEN CREATING A TOPIC)
We have few dedicated topics
on this. Most possibly you are entering your forums with 'www' in front. However they are set up without 'www' in $main_url setting, or otherwise - they are set up like 'www', you are entering them without 'www' - at the time they should only run from the same domain.