One common comment which seems to come up a lot with any midi based system issues is:
“Everything starts off fine but after a couple of hours …”
Here’s a link to a post in the General Section… it’s worth considering if “everything starts off fine but…” for you.
http://www.denondjforum.com/t/everything-goes-well-for-the-first-few-hours-but-then/1059?u=dj_boothe