I can't see where the accident report mentions mobile phones, One Outsider, the pilot was distracted by a company R/T message.
Statistically, any flight with more than a few dozen pax is very likely to have at least one active (probably inadvertently so) mobile on board. Since we don't regularly hear of resulting problems, I conclude that any risk is minimal. This view is further reinforced by the fact that airlines that can make money from it have actually encouraged the use of mobiles by providing on board connectivity.
Despite this, I try to remember to turn mine off, both because it's a reasonable requirement of the airline and to avoid annoying/inconveniencing fellow pax.