Hi, I got the same problem before. i am not sure whether is my notebook problem.
i use left hand to hold the mouse, right hand to click & hold "Ctrl" button on the right side of the keyboard, the Joint Connector can't joint together. I click & hold left "Ctrl" button can joint.
My right "Ctrl" workable for Copy / Rotate function.

TSLai88

sorry to ask help from you. I use Sketchup 7.0 free ver. downloaded sketchyphysics3 RC1 (windows installer, Jun2009). when i use "joint connector", the screen show "Requires SketchyPhysics3 RC1". The "joint Connector" just can't joint the Hinge & other component. do i need to load any other files to plugin?