One doesn't "do" grammatical errors, one makes them. Also, a native English speaker would not use the present continous tense in that sentence - he would instead write "that I do not make" or "that I would not make" (or he might omit "make" altogether).
Wrong, Richpa's use of the singular "opinion" is fine, since "opinion" can serve as an uncountable noun.
Yes, his English is pretty good though far from perfect. You, on the other hand, make many more beginner-level (see that? modifier-adjective pairs should be hyphenated) mistakes than Richpa does. Would you like me to go through your other posts in this thread pointing some of them out?
You asked for opinions on your sample material and he gave his. That wasn't a personal attack, unlike your ridiculous attempt to throw stones at his grammar from the false comfort of your glass house.