Ecclesiastes is proverbial and poetic, frequently using hyperbole. Also, the word translated "forever" ('olam) sometimes just means "perpetually." The point in Ecclesiastes really isn't that the earth will remain eternally, but that it far outlasts the generations of men that come and go.

There may have been a copying error at some point with regard to this text. Some Septuagint (ancient Greek translation of the Hebrew Scriptures) manuscripts list 3,600 at 1 Kings 5:16. We do not affirm the infallibility of all manuscripts and copies of the biblical documents, but only of the originals. Copying errors and discrepancies are not uncommon, and they do not affect significant doctrines. On the other hand, it may simply be a different method of reckoning a certain group of 300 Israelites -- Kings may include them with this group, while Chronicles may include them with the leaders mentioned in 1 Kings 9:23 and 2 Chron. 8:10.

In this story, the Midianites are the Ishmaelites (see Gen. 37:28).

Some manuscripts do indeed list Michal in 2 Samuel 21:8, but this is another copying error. Most manuscripts list Merab instead of Michal at 2 Samuel 21:8 (reflected in translations such as the NASB, NIV, NRSV, NKJV). This accords witht 1 Samuel 18:19 where we are told that Merab, not Michal, was the wife of Adriel (the father of the children mentioned in 2 Sam. 21:8).

See comment on #2.

The difference between these accounts may be one of perspective. Kings may speak from the perspective of the place where Neco (via his archers) mortally struck Josiah, but Chronicles from the perspective of where Josiah finally ended up. On the other hand, 2 Chronicles 35:24 does not actually say that Josiah died in Jerusalem. In the Hebrew, it simply says "and he died" not "where he died." The NKJV is a more literal translation at this point, reading: "... they brought him to Jerusalem. So he died, and was buried..." The difference between these readings is simply one of punctuation. The Hebrew itself is ambiguous on the point, and allows for either reading.

Here there is likely a copying error. The Septuagint shows seven thousand at 2 Samuel 8:4, as reflected in the NIV translation.

The manuscripts disagree at 2 Chronicles 22:2. Some say he was 42, some say he was 22. Some translations follow the number 22 (NIV, NASB), while others follow 42 (NRSV, NKJV). Again, this is a scribal error.

There is also a discrepancy between the manuscripts in 2 Chronicles 36:9. Some say he was 18 (as per the NIV translation), others say he was 8. This is another scribal error. The issue of 3 months versus 3 months and 10 days is simply one of approximation versus precision. Chronicles attempts to give a more exact number than does Kings.

The account of Saul's death in 1 Samuel 31:4 is what really happened. The "account" in 2 Samuel 1:10 is a lie told by the messenger in a vain attempt to win favor with David, the rival for Saul's throne. 2 Samuel 21:12 reflects the fact that Saul took his own life only in the course of the battle with the Philistines, and only because he had already been mortally wounded by them. The Philistines "struck him down" even if they did not deal the final death blow.

There does not seem to be any discrepancy in the manuscripts at 2 Chronicles 4:5. Nevertheless, this figure is probably inaccurate. Doing the geometry (using a 10 cubit diameter, 5 cubit depth and 30 cubit circumference, per 1 Kings 7:23), the sea would not have been able to hold 3,000 baths. This figure was probably copied erroneously (not a difficult mistake to make if we note the ancient use of two short vertical strokes designating "2" and three such strokes designating "3").

Luke says that this occurred "about" (hosei) eight days later. Evidently, his sources (Luke 1:1-4) were a bit fuzzy on the specific number, so he approximated. Certainly eight is close enough to six that it should be considered a reasonable approximation.