I tried sun-java (java-6-sun-18.104.22.168) and open java but the error remains. My system is Ubuntu 9.04 with the above mentioned java versions.
I’m running Ubuntu 8.04 with Java (Sun) version 1.6.0_07 on a 32-bit machine. I found this post which may the explanation for your problem.
I made a new release that uses BlueCove 2.1 (and the newer WiiRemoteJ 1.6a). It should be started like this: java -cp bluecove-gpl-2.1.0.jar:WiimoteLogger.jar org.uweschmidt.wiimote.logger.WiimoteLogger