The report says, "The data sent on 24 June did not suggest that the lander had experienced technical difficulties. Now, Philae’s internal temperature of zero degrees Celsius gives the team hope that the lander can charge its batteries; this would make scientific work possible regardless of the ‘time of day’ on the comet." There is no indication of any internal problem that would have prevented communication on previous days.
This ESA blog entry has a thorough summary of what might be causing the sporadic communications with the lander, and how it affects the mission. For the time being, "The mission teams are working on a short-term trajectory planning schedule, which is updated every Monday and Thursday morning." That will allow them to respond quickly to any change in Philae's status...but it must make it tough to do orbital science at the comet, which is quickly approaching perihelion.
The AKATSUKI will perform an orbit control for the fourth time (DV4: Delta Velocity 4) from July 17, targeting to be injected into the Venus orbit again in December 2015. The control will be divided into three performances.
The orbit control this time aims at correcting AKATSUKI’s orbit to one that is advantageous to its observations after being injected into the Venus orbit. We will use four attitude control engines on the upper part of the explorer this time to take this opportunity to also verify their performance for re-entry in December.