Printer stops extruding as it travels up z axis

Hi everyone

I just got my first printer (prusa i3) a few weeks ago, I had a lot of trouble with it, but I have got it to almost print.
When it prints it starts of fine but as it does more levels the extruder gradually stops extruding and thee model starts to go "stringy". I have had a look and when the extruder stops the stepper motor in the extruder clicks because it cant move the filament. I cant work out what's happening i have tried many times and the same problem has occured every time. It usually gets about 5mm up, before problem.
Really hope someone can help because i am close to giving up. :-)
Thanks


These are all the settings etc

Filament type: PLA
Filament width:1.75
Nozzle width: 0.4mm
Layer height: 0.2mm
Print speed: 50
Nozzle temp: 188
Bed temp: 70
Flow:100
Flow0: 100
X steps/mm: +78.74
Y steps/mm: +78.74
Z steps/mm: +2560
Extruder steps/mm: +105

Also this is a link to the product description of my kit on ebay it has some pictures and extra info:
[QcAAOSwJkJWih0g" target="_blank" rel="nofollow">www.ebay.co.uk]

... seems your filament jams - it's common, when the cold-end heats up too much, so the filament get soft and thickens long before the melting zone ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I had the same problem with my vertex k8400 and after crying for many hours i finally found out that it was a retraction problem. So you propably have to decrease the distance of retraction as well as the speed and/or acceleration of the retraction. I would suggest you to set the distance of retraction to about 2mm (or even less - it's just a starting point to see if that's the problem) the speed around 100 and accelration 5000. You can work it from there. I hope it helps.

Thank you both so so much finally got printing properly :-)