Your code really didn't make much scenes.
local myMarker = createMarker ( 928, 1590, -16.91, "arrow", 1.0, 255, 255, 0, 0 )
function warpToArena(p , matchingDimension )
if ( getElementType ( p ) == 'player' and matchingDimension) then
spawnPlayer (p, 1099.67, 1600.73, 13.05, 0, 0, 0, 0)
fadeCamera (p, true)
setCameraTarget (p, p)
end
end
addEventHandler("onMarkerHit",myMarker,warpToArena)