OK, so it's a native FS9 model after all.

So, I did a little "Googleing" and found
this.The Dreamwings site has either expired or moved, (can't find it anymore), but I'd start by changing the "point.0" contact points as mentioned.
There also seems to be an issue with weight loading. Found
this. There you'll find a partially modified aircraft.cfg file. If you have the slow/no takeoff issue, those corrections should be helpful.
I'll see if I can find a link to the model in question, and try it later.
**Is this the one?**
http://simviation.com/1/search?submit=1 ... +8&x=0&y=0**EDIT**
I just tried the model in the link above. Aside from it being WAY overweight by default, it doesn't seem to suffer the hopping issue. Might be worth the download and try?