@@ -220,12 +220,13 @@
 		end
 		s.subjects[si] = nil
 	end
 	local interpret_timespec = function(when)
+		if when == nil then return 0 end
 		local t if type(when) == 'number' then
 			t = s.duration * when
 		else
-			t = (s.duration * (when.whence or 0)) + when.secs
+			t = (s.duration * (when.whence or 0)) + (when.secs or 0)
 		end
 		if t then return math.min(s.duration,math.max(0,t)) end
 
 		log.err('invalid timespec ' .. dump(when))