As this is a Mobile Phone app and these usually depend on drivers ( kernel extensions, short "KEXTs", the culprit might be exactly that, a icompatible KEXT - although the app seems to run fine, it can't in such a case do for what it was designed.
Snow and Lion had a 32bit/64bit shared kernel and KEXTs could be either 32bit,64bit or both in order to load on boot-up correctly.
MountainLion is now fully 64bit exclusive, thus drivers that did the trick in Snow and Lion are now no longer working if they do not have 64bit code embedded. That is also the reason why some specific Mac Models are not supported any longer ( those with 32bit Intel graphic cards )
If this is the case, which I think it is - then it is up to the 3rd party vendor to act.