Rim/tire combination ruins tubes

Hi all,

I have a wheel with 700c Sun double-wall flat cross-section rims and
Kenda Kwick 700x23c tires. They are laced radially and I use cloth rim
tape. However, this combination of tire and rim seems to chew a line
into the tube at notch in which the tire and rim interface on the inside
of the tire. The result are two lines of degraded rubber along the
entire length of the tube. Even though the tube still holds air, it
leaks slowly - at least 20psi per day. Interestingly it only takes a
couple of miles for the tube to become damaged. I have replaced the rim
tape and inspected the rim for burs are irregularities, but I can't find
anything strange. The tire does not look strange, either, and if I use
the tires on another rim, or anotehr tire on the same rim, I don't get
this problem.

So... is there a solution to this problem other than not using this
rim/tire combination?

Thanks for your help,
Collin