At first I left mouse sensitivity as default 3.0. Then I tried 10.0 but the same thing happens.
And my dpi? What impact on this do dots per inch have? Anyway, I have no idea.

I only know the resolution. It's 1280x960 (4:3) but it's pixels.
Here is my jump.
http://www.multiupload.com/KYZDA6KULK
What I did after take-off (pressing 2 buttons obviously) was pushing my mouse towards me all the way. Anyway, good to know it's not some bug. Well, if it were, then others would get it too as it can't be hardware here.
EDIT: Now I guess I know what you mean by not moving mouse at all. Then the jumper simply doesn't take off and lands himself.
I changed mouse sensitivity to 1.0 thinking 3.0 is too much (maybe you have to move your mouse by 1mm to control the jump...). But that didn't help. I tried to be more "delicate" and it ended with the jumper flipping back as seen in maciej53 replays. Then I tried to behave more aggressively to get some length (but keeping in mind I will flip frontwards if I do it like I did at the beginning). No can do, at 1.0 sensitivity minor moves towards me, i.e. so the jumper is leaning out, cause flipping frontwards. I guess I've got a lot of practice to do... And that's bad because it seems DSJ4 is quite different in steering and I don't really want to stop playing DSJ3 (I'm not really that good but it's just for fun, right?). I like jumping in single player mode when I get back home from my uni.
