Edgar,

Substitute the line:

if dow(sys(10,(fec1))=1 or dow(sys(10,fec1))=7

with the next two lines:

lnDow = dow(ctod(sys(10, fec1)))
if lnDow = 1 or lnDow = 7

Remember that fec1 must be an integer that represents the number of days between the "Julian Day" and today.

Have a nice day