I need help with this too. Restart doesn't help for internet download. I also need to know what kind of files are more likely to be larger & cause memory trouble. I have no music files at all in my mobile. I have 16GB in memory in my mobile memory card.
Yeah… I have also had this problem many times.
But after the update of FB it has stopped but still occur once in a while. :D
I suspect network connectivity the culprit or too many background processes accessing that 2G net. ;)
My suggestion is to restart your 311. It had worked for my 311 back then. :D