If you're at the pilot login screen, and can't create a pilot, I bet you're running Vista or Windows 7. This is a known issue, and has been discussed previously on this (very long) thread. Solutions to the issue include:
1) Install BZ2 to C:\Users\{USERNAME}\Documents\BZ2 , and patch it up. Or, you can drag & drop your install folder of BZ2 to C:\Users\{USERNAME}\Documents\ via Windows explorer, and adjust your shortcuts.
2) Put something (preferably "/vista", without quotes) on the commandline, if launching BZ2 thru a shortcut. (If you don't know how to do this, it's probably not for you)
3) Wait for ta5.1's release. This will be some time.
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Or you can simply right-click BZONE.exe and click the Compatibility Tab and check the box that says: "Run this program in compatibility for: " and choose Windows XP (Service Pack 2)
It should work, then.