I use mplayer, but I'm not connecting over cellular. You can specify a cache size for mplayer. A larger buffer might help. Change your .mlb/config file's 'audio_player' line to:

audio_player=mplayer -cache 1024

That will give you a 1 Mb cache - that might be too large. You'll have to play around with it. I'm not sure what the default cache size is.