First forgive me as I do not know anything about your rig. On my Berkshire we have a cable slide, may or may not be the same manufacture. To keep the cables from falling out of the slot the manufacture uses a gromit placed in next to the cable, not around the cable. Ite idea is the rubber gromit fills the hole so the cable cannot slide back out. As for loosing one end in the slide I had that happen when one gromit was left off. I found that moving the slide 1/2 way in to insure slack and then using a very small screw driver I was able to reach in to the pulley and free the cable end then grab with a needle nose pliers. It took a while as the end was really jammed into the pulley. You may want to check to be sure the end did not break off. That has happened to me also. Then you need to thread a new cable. My slide is an accuslide and I got the cable from Amazon.