artifact with subsurf

Hello,
i have a tube shaped object that has a subsurf modifier attachted to it and the front edge with crease = 1.0 to make a sharp edge. Now there is a strange effect: half of the circle is showing correctly and the other half there is something wrong with the subsurf. It doesn´t give a rectangular edge, but rather a sharp edge like a “burr”. And there are showing some aritfects (see picture). What is causing this? I tried Ctrl+N in all possible configurations (whole object, only edge loop) but with no effect. What else can I try?

http://img431.imageshack.us/img431/1676/scene15yx.jpg

https://blenderartists.org/forum/viewtopic.php?t=57065

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Thank you for the link. But I believe they are dealing with a different problem. I don´t use set smooth anywhere. And my problem seems to be something with the subsurf. Here is another view:
http://img316.imageshack.us/img316/8191/scene34jh.jpg
Look at the inside of the cylinder. Right side es even (subsurf level 2) left side is “jaggy” as if there was no subsurf at all!

Maybe some extra hidden vertices/edges/faces, try remove doubles. Maybe the geometry isn’t correctly build.

I fixed the problem: I switched “Draw Creases” on and there were creases on the surface between the inner and outer mantle of the cylinder, and only on half of the segments and on a flat surface!? I deleted the faces and modelled them new with new creases.
I thought creases were only possible in a loop select?