Mounted one Dynafit ST on the Manaslu. No problem. Started to mount the toe piece on the second ski and thought I'd get the screws started them back out and fit with the toe plate for a final mount. First screw I tried it on went in fine but when I tried to back it our the nylon insert spun with it !! Can't get it out or in. Two threads showing, the rest are buried. Any ideas?