Where should I store disabled plugins?

I don’t think you need an extra directory for storing your disabled plugins. Better keep them there default location (/plugins/) and whenever you need to reactive just simple one click away! Or, if you think that plugin doesn’t help you in future, just DELETE it!

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)