The value on some boolean checkboxes can be unstable and return an error condition. This function can be used to set the value before reading it.

function FixBoolConnector(boolnode, conn)
{
try {
inv = Node.Value(boolnode, conn);
} catch(err) {
if(Node.ConExists(boolnode, conn))
Node.Value(boolnode,conn) = false;
}
}