If publicizing the donation will cause difficulty, then it shouldn't be done. For example, if advertising the donor's name will inundate him with appeals from charities that are beyond his means or interest, he shouldn't allow his name to be published. He cross-references the two places in Tractate Berachot where this statement appears. Dreams are sometimes Divine messages. Seven days without such a vision indicates that the person is unworthy of Heavenly communication.
Life is like a dream, ephemeral and fleeting.
If a person senses this, he will focus on the eternal purpose of life - studying Torah and doing mitzvot. Someone who goes seven days without sensing that this world is like a temporary dream has lost sight of the real purpose of life. Because for six days a person is busy pursuing a livelihood. He can therefore be forgiven for losing sight of life's temporary nature. I learn in the Mir Yeshiva here in Jerusalem.