The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  1
 0  X  0  0  X  X a*X a^2*X a^4*X a^5*X a^5*X  X a^5*X  0 a^5*X  0 a^4*X a^4*X a^3*X  X a^5*X
 0  0  X  0 a^6*X a^5*X a*X a^6*X a^6*X a*X a^6*X a^2*X a*X a^5*X a^4*X  X a^3*X a*X a^4*X a*X a^3*X
 0  0  0  X  X a^4*X a^4*X  X a^6*X a^4*X a^6*X a^6*X a^3*X  X a^6*X a^4*X a^2*X a^6*X  X a^6*X  0

generates a code of length 21 over F8[X]/(X^2) who´s minimum homogenous weight is 128.

Homogenous weight enumerator: w(x)=1x^0+546x^128+777x^136+3584x^140+742x^144+25088x^148+882x^152+903x^160+245x^168

The gray image is a linear code over GF(8) with n=168, k=5 and d=128.
This code was found by Heurico 1.16 in 1.22 seconds.