On RedHat 5.2/5.1 etc, swapon -s (to report swap usage broken down by swap partition) just says swapon: /proc/swaps: No such file or directory I suspect that this functionality isn't supported under the 2.0.* kernels, in which case that's about all that can be done (maybe swapon should print a better error message, though).
I have verified the error to occur when using 'swapon -s' on version 5.2 and later.
this will most likely not be fixed for 5.2. The functionality works in 6.0.