It's just a song. The proper way to say should be 沉默不代表（是）我的错。silence doesn't imply (it's) my fault. Most of the Chinese songs are about falling in love or falling out of love. So little bit incoherent. ( just kidding) Good luck in your Chinese

Interesting. >>> 沉默不是代表我的错 <<< Saying like this does have some inadequacy, or to be completely serious, this is kind of grammatically mistaken because it is saying: silence IS not imply my fault (I don't think what is after imply is a clause here). However Chinese can still understand it perfectly though it is kind of illogical. We'll perhaps just say: 沉默不代表我的错 or ditto like the sentence Ms Joan said, though neither of them very makes since. Just with correct grammar. It's rather complicated to English speakers that Chinese doesn't embody the tenses by using different forms of verbs - every verb only has one form of itself. So perhaps you could say 'XX不是在代表XX' though the verb '代表' is seldom used in an ing-tense (the present continuous tense) in Chinese.

actually，the precise form to express A does not imply B is-A不代表B。For instance，the exact form is “沉默不（能）代表我的错”。 Break down——沉默（silence）不（does not）代表（stand for/imply）我的（my）错（mistake）。Is that clear?