When a system has lots of devices Swat may abort with:

at java.nio.LongBuffer.put(LongBuffer.java:785)
at Utils.Bin.write_record(Bin.java:747)

You can find a fix here: http://blogs.sun.com/henk/resource/stuff/binfix.tar

- place tar file in your swat install directory, then 'cd /swatxxx' and 'tar -xvf binfix.tar'

You'll now have a new file: classes/Utils/Bin.class.

If that still fails then you have a REAL large amount of device. Contact me at swat@sun.com if needed.