The generator matrix

 1  0  1  1  1  X  1  1  0  1  1  X  1  1  0  1  1  X  1  1  1  1  0  X  1  1  1  1  0  X  1  1  1  1  0  X  X  X  0  1  1  1  1  0  X  X  X  0  1  1  1  1  X  X  0  0  X  X  X  0  1  1  1  1
 0  1 X+1  X  1  1  0 X+1  1  X  1  1  0 X+1  1  X  1  1  0  X X+1  1  1  1  0  X X+1  1  1  1  0  X X+1  1  1  1  0  X  X  0  X X+1  1  1  1  0  X  X  0  X X+1  1  0  X  X  1  1  0  X  X  0  X X+1  1

generates a code of length 64 over Z2[X]/(X^2) who´s minimum homogenous weight is 68.

Homogenous weight enumerator: w(x)=1x^0+14x^68+1x^72

The gray image is a linear code over GF(2) with n=128, k=4 and d=68.
As d=68 is an upper bound for linear (128,4,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 4.
This code was found by Heurico 1.16 in 0.0538 seconds.