Hmm.. are you sure that your miner is mining?
I can't see process like this
{screen} SCREEN -S cgminer -t cgminer
but I have no Natasha here, just beaglebone.
edt. Ah bmminer here, ok.

Ok, look at log file: /www/logs/lighttpd.error.log
cat /www/logs/lighttpd.error.log

Can you show me disc space, it could be the reason:
df -k