ChristiaanJ,
Knowing how difficult it can be to find a wiring fault or failure in the "real" world, I'm still totally baffled by this ACARS message too.
I suspect it probably translates to a "lack of signal" condition, but I would still like to know, too.
A possible explanation could be “bus overload”, a temporary and usually benign situation were data could be missing for one or more bus cycles (also depends on the bus protocol used).