Error 1
X: I am always delighted when I receive a letter from you. About the party on the 9th, I shall be very pleased to attend.
O: I am always delighted when I receive a letter from you. With regard to the party on the 9th, I shall be very pleased to attend.
X: About public transportation, the train services are excellent.
O: As for public transportation, the train services are excellent.
About may be used to introduce a topic (or topic change), but only in informal styles: 'About that book you asked for - I'll get a copy when I go to the bookshop.'
In other styles use with regard to, regarding, as for, as regards, or as far as... is concerned: 'With regard to employment at this company...'.
Error 2
X: About myself, this is the first time visiting this country.
O: In my (own) case, this is the first time visiting this country.
To express that you are going to start talking about your own experience or situation, use in my own case or (especially in informal styles) use as for me/myself.
Error 3
X: I was about leaving when the phone rang.
O: I was about to leave when the phone rang.
About to do something (Not doing)
