Since this is a simple reactor (choke) ballast for 240 volts, it's really easy to wire.  Basiclly the lamp and ballast are wired in series between the 240v legs.  The LINE and LOAD terminals on the PC also wire into that series, either between L1 and the ballast, or LE and the lamp.  The LINE and N terminals wire across L1 and LE.

I edited your diagram to show this.  If wired as below, it will work.  Like Nevada Willis said, you can use a cord to plug it into a dryer or 240v air conditioner outlet.  If you put black tape over the eye of the PC, and have a good lamp, than it should hum and the lamp will strike.  Since it is a reactor ballast, if the lamp is bad, there will be no hum from the ballast if the lamp is spent or there is no lamp in the socket.  If the PC sees enough light, you will hear it quickly click OFF when you plug it in.

Have you tried a new bulb? That might help diagnose.

Its been allmost 2 years ago that thequestion was asked (see hte dates)

What i'd check out is this :

Connect the lamp and ballast alone without the photocell to 24ov. it should work

If it doesnt :
 - Connect to 120v instead of 240v and replace the mercury lamp to an incandescent. It should light up. The higher power incandescent you try, the dimmer it will be - this is due to the ballast in series

 - Try to light the mercury lamp on a known good ballast (2-wire instant start fluorescent ballast will do too) and see if it strikes at all

 - If the incandescent didnt light, test the ballast alon - connect the 2 wires of it straight to 120v - it should hum and if you leave it for a minutes it should slowly warm up



Now the photocell :

Wiring the photocell across the 2 L's is ok only if the photocell is rated for 240v.If it is 120v then it will burn out

Wiring a 120v cell to 120v (using the neutral just for the cell) to switch 240v light may work for relay switching cells, but may damage electronic switching cells (ones that use triac to switch instead of relays). So check out the cell internal construction before attempting anything like this

You probably want to buy a new photocel & cover