getting a smooth movement between two points

what I want to do is to have two differnt people who are "sitting" on a prim to look like they are walking with eachother then turn and take differnt paths. now I can get the start and end cordinates as this is allways goin going to happen in the same place.
what I tried to do is make a pose stand so when they "sit" on the prim the sit target is far enough over the prim that combined with overriding the sit animation with a standing one and makng the prim transparent it makes the person looks like they are standing there normally. then I have it trigger a walking animation and enable physics and use that llMoveToTarget function. with a timer checking to see when when they have arrived by using the function to deterimain the distance between their current cordinate and the destination. then it stops the llMoveToTarget and disables physics on the prim and changes the animaiton back to standing.

this seems to work okay if the floor is perfectly flat and there's nothing at all inbetween. but if it encounters any thing on the floor no matter how shallow. they start to topple over and it almost looks like they are dooing cartwhees as they head for the destination and then freeze mid swing when it gets close enough to the target location, (I think the sudden freeze is due to the timer event turning off the physics)

is there any way i can make the system not tobble over so eaiserly? or is there a good non physics way to do this? as it's really imporant to make it look like they are walking from point to point and not just warp there.

you could try making the bases that they "stand" on larger (so they don't tip) or you could explore axis locking with llSetStatus...

Make the base phantom:
llSetStatus(STATUS_PHANTOM, TRUE);
llSetBuoyancy(1.0); // base should not be affected by gravity!
and possibly
llSetStatus(STATUS_ROTATE_X | STATUS_ROTATE_Y | STATUS_ROTATE_Z, FALSE); //as suggested by Void