We examine integrability of self-dual Yang-Mills system in the Higgs phase,
with taking simpler cases of vortices and domain walls. We show that the vortex
equations and the domain-wall equations do not have Painleve property. This
fact suggests that these equations are not integrable.Comment: 15 pages, no figures, v2: references added, v3: typos corrected, the
final version to appear in NP