Please check for any errors. Correct them for me. Thanks!!

Congratulation on your superb achievement. Your new position offers a quite challenge. And I am sure, John that you are the right person for the job. I can think of no one that deserves the promotion more than you do. Your reputation for an imaginative and effective problem solving is known throughout the industries.
You will soon be moving your office to the Executive sweet of offices. Please let me know when you are settled in your new office, and I will buy your lunch.

In the second sentence, drop the "a". There is another comma after John, because this is "direct address." In the 3rd sentence, drop "an."

Not "sweet" but "suite."

Sra