  We propose a candidate for the dual (in the weak/strong coupling sense) of
the six-dimensional heterotic string compactification constructed recently by
Chaudhuri, Hockney and Lykken. It is a type IIA string theory compactified on
an orbifold $K3/Z_2$, where the $Z_2$ action involves an involution of $K3$
with fixed points, and also has an embedding in the U(1) gauge group associated
with the Ramond-Ramond sector of the type IIA string theory. This introduces
flux of the U(1) gauge field concentrated at the orbifold points. This
construction provides an explicit example where the dual of a super-conformal
field theory background of the heterotic string theory is not a standard
super-conformal field theory background of the type IIA string theory.
