grammar mistakes in letter

Dear Sir/Madam,
This recommendation letter is for Mr. Kishore Kumar Akula. I know him since 2002. I taught him Education Technology during his B.Ed.
He has very high potential in using computers in education. He wrote many software programs for the summer and in service teachers’ programs. He has very good grip over the educational technology subjects. He has shown tremendous amount of skills in applying the educational psychology principles in education technology. He can very easily understand the needs of the students. The technology he uses will fulfill the needs of all types of students including slow learners as well as the gifted students. If an admission is given into M.S or PhD, he will use those skills and knowledge to create some tools which is useful for easy learning and will establish his own theories in the learning process. I strongly recommend him for the admission into M.S/PhD.
If you need any further information, please feel free to contact me.

Here's one mistake:

I know him since 2002.

This should be: I have known him since 2002.