Do you know what it means in the control panel when it says '[MASTER] work received - share target' ?
It mean that the pool is sending you correctly the work to do.
In some case, when you leave Putty (or equivalent), it stop the active session. To solve this you can use tmux like this :
sudo apt-get install tmux
tmux
cd ~/ptsminer/src
./ptsminer Ppfk7DMY7wCpFfLUnSVijGwruPq3Y3WJF9 1 26 sse4
(replace with your settings)
press Ctrl-b then d to close session
tmux attach -t 0 to resume session (0 is the number)