I hope i am not confusing you.
If you indeed have an o2 Blackberry Bolt on. Do you have an email settings icon on the device? if so, go there and set up your email, create a username and password too as this can be used to go to the o2email.co.uk website. How to add / delete email addresses - BlackBerryFAQ
It is important that you create a username and password here.
Was this a second hand device? Your answer may make things a little cleaer.