Please help with me with grammatical structure

In the following sentence, in terms of correct grammatical structure why is am incorrect? :

I am absolutely agree with you

First because it sounds funny.
It is not necessary, because you already have the verb "agree" in the sentence.
If you want to word the sentence, "I am in absolute agreement with you", then you can use the present tense verb "am". Otherwise, just say "I absolutely agree with you.