salut pichart,
with os x' prview, i don't see the black rectangle and black line in the attached pdf...
with acrobat reader i see unusual things but they could be normal, as i tend not to use acrobat and i don't know exactly how it should behave...
in the .sla you have a filled text frame on top of an empty one... but, at first sight, i don't see anything that should produce a black rectangle the line...
where should they be?
ciao
a.l.e