Just to help the people above, To run a multi scart correctly you should only have one of the devices which attaches to the multi on at any given time.
If any more than 1 is running then your tv will recive a garbled mess of information like the user above says.
The Tv will find all the hardware attached, nearly all tvs have av 1 or av 2, which is where the scart connects to tv, aslong as you have the correct av channel on, and one of the hardware turned on, you will get a picture of from that given hardware, being a Skybox, freeview, dvd, vcr or even a computer.
I Do recommend looking for a semi decent one thou, a cheap one like above is more of a temporarily solution to see if things work etc.