Construction line question?

 From:  all2000 (SPEEDY)
991.10 
Hi Michael and Forun Friends
I try the script to activate (Keep Costruction line, but it's not run , when hold K key show
this message ?????
What's mean .....
again
I ask you will be ,in the futur , for Moi user the Plug-in Tspline
actually for Rhino ??
Tnx
Sorry for my English
Al