The meaning of "Yom": How do we set church doctrine?

I read recently that the Hebrew word used in Genesis to describe the Creation story ("Yom") could have three different meanings. One is a 12 hour period. Another is 24 periods of something (24 seasons, 24 days, 24 years, etc. The last possible meaning is "a time period". This could mean a season, a year, a millennium, etc.

I'm no language expert- and surely don't know Hebrew (so I might be entirely wrong), but if this is true then a literal translation of the Creation story may be problematic. Do we really know what the "literal" translation is?

One theory I've heard to solve this "problem" is that the King James Version was inspired by the Holy Spirit in such a way as to be a translation we can count on being literally God's words.

In going to the website http://www.religioustolerance.org/ev_world1.htm, I saw these interesting theories on the Genesis account of Creation:

1- It happened exactly as the Bible- in its current English translations- says it did (God created the world in 6, 24-hour periods)
2- God created the world in 6 days, but the days were not contiguous- there were long periods of time in between each day.
3- God's "days" are a thousand days to a human "day"- therefore it happened over 6,000 days.
4- God's "days" are "like" a thousand days- so they could be any time period- to us they are long, to God they are "only" a day.
5- The Creation story is a metaphor- not meant to actually describe what happened, but to give humans a model from which to follow in as far as work, worship, and rest.
6- Each day represented millions of years
7- God did create the universe in 6 days, but it happened a long time ago (unknowable).
8- The author of Genesis used a narrative device to describe the Creation in "acts"- instead of "Act I", he used "Day 1". In other words, it is impossible to know how long "Act I", etc. was.
9- God described the Creation to Moses and took 6 days to describe it. Moses described the illustration.
10- God commanded Creation to take place over 6 days, and then it took a much longer period to take place
11- depending on your "time perspective" (since time is relative), from God's perspective (outside looking in?) the days were short. From our perspective (inside?) it would have been billions of years- but even that is problematic- since "we" weren't around billions of years ago. (this theory somehow agrees very closely with Big Bang Theory calculations for the age of the Universe)
12- and, my "favorite" : "...Replicated earth theory: Mike Schuler has developed a novel theory of origins, and has begun a web site to explain this and other scientific puzzles. He believes that God created an original earth. He spent billions of years trying every possible genetic code, to see what types of life would result. Most of the species were useless. God created a mass extinction event whenever the world filled up with such unneeded species. At the end of this great experiment, he was ready to create humans in the image of God. So he created an exact copy of that original earth in perfect detail, down to the atomic level. This took him only six days, as Genesis states. Schuler draws the analogy of the creation of a music CD. It might take months to create a new CD, but a copy can be created in seconds..."

I, personally, have one question for all of the theories which hold that it had to have happened (any part that God took direct part in) in a certain time period. For an omnipotent God, why would it not have happened instantaneously? It would seem to me to be more believable that it really was a metaphor to show us how to live, and that in reality it happened in a way most likely only known to God.

The science fiction lover in me, however, likes the "time perspective" theory. Time being relative is very hard for the layman to understand (me being one of them). At the start of the Big Bang (if the theory is right), time, space, and matter were compressed in ways beyond our understanding. To explain how it really happened, one would have to know from what perspective it was being described. Since humans weren't around according to the Bible- it would only follow it wasn't from our perspective.

In the end, however- it should only matter how it happened if it effects the central tenets of our faith. Does it?