Index: /issm/trunk-jpl/src/m/classes/plotoptions.m
===================================================================
--- /issm/trunk-jpl/src/m/classes/plotoptions.m	(revision 19404)
+++ /issm/trunk-jpl/src/m/classes/plotoptions.m	(revision 19405)
@@ -129,8 +129,8 @@
 							 nums=strsplit_strict(plotnum,'-');
 							 if length(nums)~=2, continue; end
-							 if ~isnumeric(nums)
+							 if isempty(str2num(nums{1}))|isempty(str2num(nums{2}))
 								 error(['the option #i-j is not set properly for ' field]);
 							 end
-							 for j=nums(1):nums(2),
+							 for j=str2num(nums{1}):str2num(nums{2}),
 								 opt.list{j}=addfield(opt.list{j},field,rawlist{i,2});
 							 end