The AT-ST Walker that is wind-up is refered to as "AT-ST STRUCTOR Tructor Model Kit" I think. I remember buying them for my kids to build in the mid 1990s, when they were 5 to 7-ish in age.
I did some searching, and both the Ertl and AMT kits are around the web. I forget which one was the wind-up walker, but may have been both.
~Aric Fisher
aric_001@hotmail.com