1)
What is the tense of "Habita"?
1.
Rav Sadya Gaon: It is past tense, written as a command.
2.
Ri Kara: It is a command.
2)
What is the meaning of "Ani Manginasam"?
1.
Ibn Ezra: [When they lie down and rise,] they sing about my demise. Manginasam is like Neginasam (their song). The Mem at the beginning is extra. Ri Kara - the verse should be re-arranged. It means Habita she'Ani Manginasam b'Chol Shivtam v'Kimasam.
2.
Palgei Mayim: I am in place of a song for them. They constantly jest about me.