@thorn36,
Is this what you are talking about?
"A sequel to Trapped. Led by the ever-resourceful Ryan Cavener, the kids eventually find a way to reach the research island only to discover their parents have been kidnapped by the increasingly unstable Dr. Hamilton. Six months pass with the kids staying on the island hoping either their parents would return, or someone would come to rescue them. Nobody comes. Desperate to find out the truth, they build a raft in an attempt to reach civilisation and get help to rescue their parents. However, the raft doesn't survive the stormy crossing and now they find themselves... Castaway."
Airing in 2011
http://www.australiantelevision.net/castaway/