another glitch !!?

[bender9o]

hi all, just joined to ask about a problem im having, ive got total overdose on ps2 an its been fine up until now, im on the level where you have to get 3 trucks out of the dock area, and everytime i try an go for the first one it disappears an re-appears somewhere miles away on the map (not even in the dock area) when i go an try an follow it, i find that its completely off the explorable map, so i keep reloading the game an trying again but the same thing happens? does anyone know a quick fix that i can do? or do i have to start again?