I think you've got some setup errors... It appears you are mixing Strings and char arrays and pointers to char.
you declare this:
char* myStrings[64];
and then within setup, you do
myStrings[j] = buffer;
which just assigns the address of buffer to all elements of myStrings[]. It doesn't actually copy the data since in is not a 'String'
You also do this:
char mpass[ ] = "command" ;
int num = j;
char cstr[16];
itoa(num, cstr, 10);
strcat(mpass,cstr);
which is overrunning mpass. If you want to have room to append things, you have to create a larger array or use the 'String' class.
I personally don't use the String class (just use char arrays) but it is easier for newer people to understand and usually does what they expect with assignment and concatination, etc.
My guess is that you are not setting up the mux correctly from your ini file