Drawbridge script W/ Ropeconstraints , where is the error?

gate = script.Parent.Parent.Gate
ropelength = gate.RopeConstraint.Length

function onClicked()
    while ropelength >= 0 do
        ropelength = ropelength - 0.2
    end
end

This does not work, the part "gate" is unanchored. The ropeconstraints and attachments are in their correct places.

Where am I going wrong with this?

All help appreciated.