AI Planes bouncing/Planes sinking in tarmac

Dear all, you are reading a man in despair...It is a long mail, but I really need your help so I am trying todescribe the issue as precisely as possible... Please read it if youthink you can help... You will make my next week-end...I had a weird problem a few days ago...I was trying to make my first network flight, with a new plane Ididn't knew too much, the POSKY CRJ in Air Littoral livery...It went bad, as the plane was going on "diving" in the tarmac...AI planes were as well stopped in the air at stupid attack/roll anglesa few meters AGL...As I had installed a few add-ons without really testing them, Iassumed it might be the reason why...I started investigating but didn't really find consistent things... SoI had to re-install... What I started a few days ago... I dideverything right and quietly. Installed FS2002 vanilla flavour, thencustomize it, then install addon modules (FSUIPC, ActiveCamera,...) asmall selection of add-on planes, then sceneries... AT each stage (ornearly) I was trying one of the situation that were so odd before.And everything was working fine...After a "hands on" flight in Yannick Lavigne's Falcon 50, I came backto my first project of netywork flight... I then created a new flightthe POSKY CRJ at one of the gates of LFPO (sorry, I am French), savedit, prepared my maps... It was happyness...Then I actually started the network connection (not from within theflight), and opened the flight... and...THE CRJ SANK IN THE TARMAC AND CRASHED (OBVIOUSLY) !!!!It was 3 hours ago... Since that I tried a few more things, here iswhat I can say :*Some plane are affected, some aren't.*the only of mine "player plane" that seem to be affected is the POSKYCRJ. Others, Falcon 50, Robin DR400 (both Y. Lavigne), B. GrabotskyERF145 are not crashing, nor diving in tarmac. Std B737 neither... StdC172 might have ones at Meigs... not sure...*Altough for the planes that are not diving in the tarmac, the flightseems to be initiated high or very high AGL... Never noticed thatbefore, but I don't know if it was not already happening.*It happens anywhere (taxyway, runway, gate...), and not only in LFPO(Tried Meigs and LFMT).*AI planes are doing funny things, but not all of them... I saw a MD83(I think) swinging and bouncing on the tarmac then stopping at 30