The Bible, being a book with only one correct interpretation, was never designed to support the vast range of denominations that claim allegiance to it. The fact that so many denominations exist leaves every Christian with one vital question: What do I do when the Bible disagrees with mine?
Because of the nature of Christianity, not every Biblical error is "fatal". Many errors are trivial at best. Other errors, however, are big enough as to rock the boat a bit, and others are enough that you can safely assume those who hold to them are either not saved, or are close enough to the line between Heaven and Hell that they really ought to be panicking. How do you judge any of these errors, and how do you respond when you have found one?
The comment in the screenshot above is from a discussion I had with a Catholic. His views may not be typical of the Catholic Church in general, but it's clear what his answer to the original question is. When the Catholic Church and the Bible disagree, this man believes it is the Bible that is in error.
Now, picture the following scenario. God comes to Earth and visits the Pope. He and the Pope stand before a congregation of Catholics, and God begins to preach about some of the errors in the Catholic Church. All He does to do so is say "you Catholics believe (insert current Catholic source here), but my word says (insert Bible quote here)." The Pope, visibly angry, eventually says to God "Enough! We do not get our authority from your word! Your word gets its authority from us!" What do you think God's response would be? Would He shamefacedly obey the Pope and go to sit in a corner, or would He put the Pope in His place?
To answer that, let's look at the very first time the word of God ever came to man. Let's go all the way back to the Garden of Eden, when God only gave three commands to man: Fill the Earth, have dominion over the Earth, and do not eat from that tree. It is clear who the authority figure is here. God gave a command. Adam broke the command. God punished Adam. The logical conclusion, then, is that when God gives a command, Adam (i.e. us, his descendants) must obey. We don't get to decide when to obey God's word! Failure to comply with God's word results in punishment, even if the word is in written form now.
Now, to be fair to all Catholics, this particular individual may not be typical. In fact, in my experience, Catholics have a wide range of opinions on the word of God. Some have held it in high enough regard that when they have been shown the Biblical errors of the Catholic Church, they have left. Others, by contrast, have flat out rejected the Bible as the word of God. I've seen all of this and everything in between. But whatever your personal view of the Bible, the fact remains that it is the inspired, authoritative word of God, and thus those who claim to follow Him have no excuse for remaining in a denomination that so brazenly disagrees with it in a number of areas, both great and small.
Although this post mainly addresses the Catholic Church, the same principle applies to all things Christian. Christians are commanded to test all things (1 Thessalonians 5:21; 1 John 4:1), and thus it is important that even your most firmly held beliefs be tested rigorously. Always ask yourself "why do I believe this?" and "does this belief stem from the Bible?" If the answer is no, especially if your belief is against the Bible, it is vital to let it go.