There is a very good reason why the scart to component lead is not working - and its got nothing to do with a dud lead!
On most TVs and screens scart does not carry a component signal.
AFAIK the only TVs that do have component via scart are a couple of Lowe TVs.
Scart normally carries (from bad to best) composite, S-Video & RGBs
I think your best bet for connections would be to get a component input board for your plasma or see if you can set the DVD to output RGBs via the component sockets.
Mark.