The generator matrix

 1  0  1 X^2+X  1  0  1 X^2+X  1  0  1 X^2+X  1 X^2  1 X^2  X
 0  1 X^2+X  1  0  1 X^2+X  1  0  1 X^2+X  1 X^2  1  X X^2  1
 0  0 X^2  0  0 X^2 X^2 X^2 X^2  0  0  0 X^2 X^2  0  0 X^2
 0  0  0 X^2 X^2 X^2 X^2  0 X^2 X^2  0  0  0  0 X^2  0 X^2

generates a code of length 17 over Z2[X]/(X^3) who´s minimum homogenous weight is 16.

Homogenous weight enumerator: w(x)=1x^0+190x^16+64x^20+1x^32

The gray image is a linear code over GF(2) with n=68, k=8 and d=32.
As d=32 is an upper bound for linear (68,8,2)-codes, this code is optimal over Z2[X]/(X^3) for dimension 8.
This code was found by Heurico 1.16 in 41.5 seconds.