It's unlikely the bottle would leak so I'm surprised he suggested that, maybe you mean where the hoses join onto the bottle?
I'd start by cleaning up the area if you can, best plan is get it on a ramp, if you have any friendly local garages you can ask, it may be be a wise idea to see my if they can take a look for a very small fee/free, saves messing about with jacks and such.

They tend to leak from either the rack itself, or most commonly the hose which joins on to the pump, where the metal part crimps onto the rubber hose, only way to sort that is get a new hose, as stated above GGR sell these or you can get an adapter for the rack and use a hydraulics company to make up a new hose. Not a very big system so it should be easy to find the leak.