Solving that problem is on my list also. I found this site (
http://www.ptreeusa.com/uhmwproducts.htm) which has Ultra High Molecular Weight (UHMW) plastic strips which I plan on putting under the doors and some short lengths installed on the bottom of the doors where the rollers are now. That will put slippery plastic against slippery plastic and, hopefully, solve the problem.
dvd