Inerrancy and 1 Peter

Awhile back I talked about the concept of inerrancy and Ephesians 4:8 and Pslam 68. In the recent Bible study I facilitated we ran into a similar example in 1 Peter 4:18. This verse is rendered in the NIV as:

And, “If it is hard for the righteous to be saved, what will become of the ungodly and the sinner?”

This verse is a direct quote from Proverbs 11:31. As with Ephesians 4:8 there is some confusion over this verse and its proper translation. It appears that the author of 1 Peter was quoting from the Septuagint, the Greek translation of the Old Testament made around 250 BC in Alexandria. There the passage says basically what Peter quotes - namely that if the righteous are saved by the skin of their teeth, then what chance do sinners have.

However, in modern Bibles, including the King James, based on the Masoretic text (the Hebrew version, earliest extant copy from 1000 AD) Proverbs 11:31 does not refer to salvation at all. For example, the NLT translates the passage:

"If the righteous are rewarded here on earth, how much more true that the wicked and the sinner will get what they deserve!"

While the NASB has:

"If the righteous will be rewarded in the earth,
How much more the wicked and the sinner!"

These appear to be in opposition to 1 Peter’s rendering focusing instead on how the righteous are rewarded here on earth while sinners will get what they deserve. To me the differences call into question the doctrine of inerrancy and point to the probability that the author of 1 Peter used a faulty translation of Proverbs 11:31.