Originally Posted by fly-yul
Follow the step by step instructions at truphone.com
They walk you through not only the installation process but the upgrade firmware process too.
http://www.truphone.com/scn/more_info/what_phones.tru
To use Truphone you will need the latest firmware (get this from Nokia Software Update):
http://www.nokia.co.uk/softwareupdate/
on the E60 and E61, you will need firmware version 2.0618.06.05 or later.
To check the firmware version installed on your handset, press *#0000#. You can update your phone's firmware yourself by downloading from Nokia Software Update. See our help section for information.
Depending on where the E61 comes from, the Nokia Software Updater may not recognise your own phone and tells you that no update exists, when in fact it does. That is the issue covered in the thread I linked in my post above.
That was also my exact problem, now resolved.