Item update position problem

Hi All, i am trying to move my item object ( on circular path , i tried with script but it was not smooth ). Then i moved all update position to engine. Now its smooth but there is difference in update between server and client ( i.e object bounding box is at different position and object is at different position )

here is code ( void Item::processTick(const Move* move) )
if( mDataBlock->mRotate && isPlayerSet )
{
Point3F pos;
mObjToWorld.getColumn(3,&pos);
int rotCount = Con::getIntVariable( "$refangle" ) ;//dAtoi( rotateCnt );

fRotAmt = ( pLayerCount * 0.624) - ( rotCount * 0.005 );
MatrixF mat = mObjToWorld;

F32 newXPos = 362.00 + 4 * mCos( fRotAmt );
F32 newYPos = 430.58 + 4 * mSin( fRotAmt );
mat.setColumn( 3, Point3F( newXPos, newYPos, pos.z ) );

pLayerCount++;
if( pLayerCount > 10 )
{
pLayerCount = 1;
}


pos = Point3F( newXPos, newYPos, pos.z );
this->setPosition( pos );
//Parent::setTransform( mat );
updatePos( isGhost() ? sClientCollisionMask : sServerCollisionMask, TickSec);
}

what is wrong in this. After hour of debug i found that there is problem with updatePos
but if i removed it then the movement is jerky.

// If on the client, calculate delta for backstepping
if ( isGhost() )
{
delta.pos = pos;
delta.posVec -= pos;
delta.dt = 0;
}



This part of the code is causing problem. How i can have update both server and client position simultaneously?