Since you open a new thread, you should copy here the English phrase in order for people to know what you need help for. The phrase is "I drive an immortal light of unconquerable knowledge lasting an age".
My translation is in ancient Greek; the one that you add on this page is in modern Greek. I don't know if you copied this translation as it was given to you, but the genitive "τῆς ἀκαταμάχητης γνώσεων" is not correct; it should be "τῆς ἀκαταμάχητης γνώσεως". The addition also of the article is wrong, since it is not in the original. Your modern Greek translation should be "ὁδηγῶ ἀθάνατο φῶς ἀκαταμάχητης γνώσεως ποὺ διαρκεῖ μιὰ ἡλικία" - or, if we consider the age to sum up eternity (since this knowledge is invincible and the light eternal, normally it lasts "all time") "ὁδηγῶ ἀθάνατο φῶς ἀκαταμάχητης γνώσεως ποὺ διαρκεῖ στὸν αἰῶνα."