The generator matrix

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

generates a code of length 69 over Z2[X]/(X^2) who´s minimum homogenous weight is 66.

Homogenous weight enumerator: w(x)=1x^0+82x^66+85x^68+44x^70+1x^72+14x^74+17x^76+2x^80+4x^82+6x^84

The gray image is a linear code over GF(2) with n=138, k=8 and d=66.
As d=66 is an upper bound for linear (138,8,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 8.
This code was found by Heurico 1.16 in 19.4 seconds.