What it means is that people are gullible. The bible means as much as nemo and unicorns do. They are stories written by people so long ago and now people think that it is true. I know that may not be what the question was really asking, but it is the truth.
It is quite possible to understand what the Bible means. In point of fact it is quite simple. A lot of people out there will argue that the language is lost to us. At one point in history, Hebrew was thought to be a lost language. However, the revival of the language has been successful beyond question. Koine Greek is not so precarious as people like to think. In fact the language has survived in all sorts of writing and we can easily place various documents together to examine meaning, as linguists are want to do. The language is easily discernable, and this fact is easily backed up by scholars and linguists and literature folk from the Dons of Oxford on up to reporters today like McDowell and scholars like Erhman (who has written extensively on this topic).
Three simple rules to follow when comparing ancient documents: Rule of Definition, Rule of Usage, and the Rule of Context. So long as the lexicon and the diction hold true to these three we're golden.
"But the Bible has too many authors and was written in too many lanuages and it's just not possible for it to make sense." Yeah, but then mysterious things do happen. We can substantiate the various claiams made by the authors by simple comparison. Guess what? no truly worthy conflicts of note appear--i mean yeah, someone missrepresents the size of an army or something like this, but those aren't of consequence because they aren't essential devices with in the text.
Secondly, we look to the historical record just as you authenticate any ancient text. How do we know about the lighthouse in Alexandria when there are no traces left? We look at historical texts. So...let's chech archeology records--yup, support. Let's check historical documents -- yup, support.
Thinking outside the box, if a person is a person of faith the Bible is not ambiguous. It is the revealed word of God. In this, we can very easily determine the meaning of the word because God would have seen to it's survival. How do we know this? Well it's rather simple, the Dead Sea Scrolls are thousands of years old and scholars have compared those scrolls to the writings of today and the difference in the language is considered negligible. The truth is has survived.
Let's take it a step further, how about those images and prophecies? Well, to understand these we need to glance through the lense of time. Revelations speaks of an angel holding a scroll with seven seals, and a lamb that appears slain is the only one worthy to take it. OKay, so we already know that Jesus would be the lamb, that's basic Sunday school, but what about the scroll with seven seals? Well, look at old hebraic laws. That is a deed to land. The writing on the outside is the agreement, the seals are set for the jubilee. This isn't really difficult stuff.
Their are 2 ways to read the bible; literally and critically. You can take the passages word for word, but it will make no sense and you will just think of it as a guy telling you what to believe. If you read it critically, on the other hand, you will read between the lines and find the true meaning of what the author was trying to say. Just as an example, there is a passage that says Jesus took water and converted it into wine at a party. What it means is that the people at the party had so much faith in Jesus that they believed the water was wine.
Overall, the bible could be interpreted in many ways, though it is all up to the reader to put the text into a concept that he/she agrees with.
Given how long it must have been since the bible was first told or written we can only assume that as the bible has been translated some things have been lost. For all we know it could have been a bed time story. But unfortunately unless we create a time machine and find when the bible was created and who created it then it is impossible to know what the author intended the bible to mean.
It is not possible to determine the absolute meaning of a text without first defining the text in a language that removes all ambiguity. Greek, English, French, Spanish, and any other world language contains many phrases that may have many different meanings depending on the interpretation and context.
For example, the placement of just one word in a sentence can have a large impact on the meaning of the sentence in the English language. "Only I hit him in the eye yesterday" may translate to "No one else hit him in the eye yesterday", while "I only hit him in the eye yesterday" may translate to "I exclusively hit him in the eye yesterday", while "I hit him in the eye only yesterday" may translate to "I did not hit him in the eye any day except yesterday."
If the Bible was written in the language of Mathematics, a perfectly precise language, perhaps then we may determine exactly what the Bible 'really' means. But we are burdened with a book that has been seen passages added, passages re-written, and passages destroyed. It has also endured several translations from language to language.
As a collection of ancient texts written over a period of centuries several millennia ago by writers who in many cases have been themselves long lost in the annals of history, and compiled against the backdrop of internal church friction and political competition, the Bible's meaning can never truly be know to modern readers.