This is a tricky one, I have the following output:
mysqldump: Got error: 1045: Access denied for user \'root\'@\'localhost\' (using password: YES) when tr
In Past same problem occurred to me after I copied the mysqldump statement from a MS Word file.
But When typing the statement directly, everything worked fine.
In hex editor the "-" of the not working statement was represented by the unicode char e2 80 93 (http://www.fileformat.info/info/unicode/char/2013/index.htm)
In sort, type password directly and check the copy paste code as the uni-code (or other encoding) strings might cause an issue..