Something else must be going on Big Bob..
Works here + both REAPER and the SWS extension have a protection against récursive actions - "recursive" like a srcipt calling itself directly or via macros or via (cycle) actions so that it would call itself again, and again, etc... and would eventually crash (stack overflow).
to make sure, please can you please a ticket in the
SWS tracker and attach your scripts and Cycle Actions there (use the export function of the editor)?
on a sidenote: sws tracker = better support in the future!