http://wiki.mikrotik.com/wiki/Manual:License
router needs to be able to get online dns and def gate needs to be set, ping
http://www.mikrotik.com from the command line to make sure its all fine.
New 8 symbol SoftID
Since RouterOS 3.25 and 4.0beta3 new SoftID format is introduced. Your license menu will show both the old and the new SoftID. Even by upgrading to a new version, RouterOS will still work as before, but to use some of the new features, LICENSE UPDATE will be necessary. To do this, just click on "Update license key" button in Winbox (currently only in Winbox).
New SoftID's are in the form of XXXX-XXXX (Four symbols, dash, four symbols).
The following actions will be taken:
Winbox will contact
http://www.mikrotik.com with your old SoftID
http://www.mikrotik.com will check the database and see details about your key
the server will generate a new key as "upgrade" and put it into the same account as old one
Winbox will receive the new key and automatically License your router with the new key
Reboot will be required
New RouterOS features will be unlocked
Important Note!: If you see this button also in v3.24, don't use it, it will not work.
If you ever wish to downgrade RouterOS, you will have to apply the OLD key before doing so. When RouterOS applies the NEW key, the OLD key is saved to a file, in the FILES folder, to make sure you have the old key handy.
Even more important: Don't downgrade v4.0b3 to v3.23 or older. Use only v3.24 for downgrading, or you might lose your new format key.
For interest sake what ver of ROS are u trying to install and with what NETINSTALL, also have u updated the firmware?