Here.
Wefco Rubber.
http://www.wefcorubber.com/
The replacement stuff for Ericsons are:
Track = Profile# 0422 G
Insert = Profile# 788 (for some reason this one is not cataloged on
their site, but if one knows the numbah, one can order it).
I am not replacing my track so I don't know much about it, but since I
bought the insert, I can tell you that it is made of EPDM, comes in
black, grey, or white, and the black cost $3.00 per foot. I recall that
the white costs more.
Guy