I am a newbie in 3d printing and had similar problems in the first 2 weeks after building the Ultimaker. Printing simple objects was difficult at first, had to set the temp at high values, 250C to get a "normal" flow of PLA for extruder. Then sometimes the filament get stuck or the next day I spent a lot of time getting the PLA out of the extruder. My filament was also stripped and get stuck in the bowden cable. In my struggle to get good results I changed the spool of black PLA with another one silver PLA. Then I noticed that the black PLA was soft and the silver one was hard. After this change the printing went well (low temp 185C), almost easy except of course from the normal "newbie" problems, calibration, settings, software issues. In my case I was printing with soft-PLA and it was hard to get a normal print, is it possible that you are using soft PLA as well. I haven't had much luck printing good objects with this type of PLA and don't know what to do with it either.