At first time you start your code dcl_lst is nil, so string
(stringlistregistrywrite "HKEY_CURRENT_USER\\SOFTWARE\\Maestrokey2"
"Maestrokey22"
(cdr (assoc "key_ListNotas" dcl_lst))
)
writes empty string. Your code has too many global variables (biblioelecversion; dch; dcl; dcl_lst; ddiag; des; maestrokey22; savepath). I propose convert them to local. And execute your code step-by-step.