App crashes during memory release
This usually happens when the device has been running for a long time without a reboot. Basically, iOS cannot find enough memory for System Status and kills it. In these cases, it's best to restart the device, because the same thing will happen with other apps that need larger amounts of memory.
Personally, I'm not a huge fan of the "memory release" feature — I implemented it only to silence all the user requests. Have a look at the documentation for more details: