Has God's revelation through Scripture been overtaken - on some aspects - through the passage of time and its associated changes to social circumstances? If we thought that God said something about X that was relevant and applicable in (say) 150 AD, could it be possible that that same thing is now no longer relevant and applicable in (say) 2010?
I appreciate very much that behind such questions lies a concern for honouring God and God's Word revealed to us. For myself I would not want to be propagating lines of hermeneutical enquiry which led to conclusions in which the church was effectively saying "God was right once. Now we know God is wrong." God is always right; we, many times, are wrong!
At all times we need to take care in how we handle the Bible. Just as we can dishonour God by mishandling in one way, so we can cause pastoral mayhem by mishandling in another way. Currently in NZ, for example, we are now receiving fairly regular news reports of the destructive effects on poor Christians belonging to the Destiny Church due to Bishop Brian Tamaki's understanding of what tithing means in relation to his income (they give, he receives) and what income he deserves because he has been faithful to God (a lot lot more than the least of his brethren).
In my understanding at least three possibilities for "change" to our understanding of Scripture need not incur the charge that we think God was right once but is now wrong. (I acknowledge that the three possibilities are probably variations of each other!)
(1) We think Scripture points us in one direction but events press us to reconsider our understanding of Scripture. The conclusion we reach is not that God is wrong but that our understanding has been wrong. The classic example (in my view) would be slavery. Many fine Christians (including George Whitefield, I learned recently) have been comfortable owning slaves. Now that is not so. Our understanding of slavery and its rightness or wrongness has changed, not least because we have changed our understanding of what it means to be a human being: an African, for example, is not a lesser being than a European.
(2) Over time we review not only what Scripture says, but our attitudes to something. A good example in my view would be alcohol. Many a zealous Christian has been dead against alcohol and found texts to support that view. But over time attitudes have changed and Scripture has been read more carefully: it warns against drunkenness, it does not prohibit consumption of alcohol. A number of my Christian friends used not to drink, but now they enjoy their chardonnay and shiraz!!
(3) We change our minds about applying a principle in Scripture. The principle stands, but for various reasons our commitment to applying it is revised. An example would be capital punishment. The principle that a person taking the life of another person forfeits their right to live still holds. But for various reasons - from a new appreciation of mercy to a necessary recognition of the irreversibility of a wrongful judgment by a court - many Christians no longer support capital punishment as an option on their nation's law books. God is not thereby proved wrong, but we show that we have freedom both as humans and as Christians to vary the way we govern ourselves.
There is one further issue which has been mentioned in comments. (In my words) the issue is that God is made deficient in his provision for us if we allege that the written Word of God does not provide for a situation which arises - the deficiency could be that God is imperfect in his power because God is unable to see sufficiently far ahead in respect of what changes in life will arise.
I do not think the Bible is intended to provide for every situation that conceivably could arise in the permutations of human life. If it was, would there not be a smidgeon of material which applied to the various issues arising around genetic engineering, IVF, stem cell research, and the like? Or, what about a clear, ever relevant ethical theory about going to war? Wisely the Anglican reformers said both that Scripture was sufficient for salvation and agreed that the church may make decisions on matters not expressly touched on by Scripture.