Is it possible you're hanging onto the tubing too tightly or at the wrong angle, so it pulls up the sticky part? Also, be gentle when you unwind the tubing and when you pull off the tape.
I've rarely had a problem with the Inset 2s (9mm) - occasionally yes, but I can always explain it.
There's one of many YouTube videos: http://www.youtube.com/watch?v=Jg0xdlpEfSA
I don't do things in the same order she does, but the prep and insert technique is not bad. Also make sure you are placing it and holding it firmly against your skin before you trigger the device. Before you pull off the housing, press down in the middle to make sure it's all sticking properly.
Here's one I learned from: http://www.youtube.com/watch?v=klkLnhiHeHU. Again, about something different, but good technique, although I press it against my skin a bit more firmly than she does.
There are lots more videos! We can't see what you're doing but maybe you can watch to compare.
Hope that helps!