This looks like a hoax. If you look at the decoding ring, it's more complex than the message is in the first place. There are even duplicates in their decoder ring. Sa means 4 different numbers, and 7 duplicates in their decoder ring. Using their decoder ring (using the first "meaning" of any number, I get (text, value according to their decoding, value from pi approximation) :

[('go', 3, 3),
('pi', 1, 1),
('bha', 4, 4),
('gya', 'UNKNOWN', 1),
('ma', 5, 5),
('dhu', 4, 9),
('vra', 'UNKNOWN', 2),
('ta', 1, 6),
('srngi', 'UNKNOWN', 5),
('so', 5, 3),
('da', 3, 5),
('dhi', 4, 9)]

It's close, sure. But not better than other random stuff.

In "lorem ipsum" text, translating a->1, b->2,... you find 3141(391491322514) at position 170 onwards. And the collected works of william shakespeare (as downloaded at http://www.gutenberg.org/cache/epub/100/pg100.txt) contain the following "PI approximations" (encoded as above):

3 => 290159 occurences
31 => 116402 occurences
314 => 7913 occurences
3141 => 3970 occurences
31415 => 1650 occurences
314159 => 39 occurences
3141592 => 8 occurences
31415926 => 0 occurences

Shakespeare must have been a closet mathematical genius ! (Hmmm, I guess he lived after the discovery of Pi, ... oh well, still makes the point I guess)

Even the bible contains actual approximations to pi (for example the surprisingly accurate 22/7). It even makes sense that it does. For a lot of history the bible was effectively the only book available for a large percentage of the population (and even then, often not directly). It seems the authors knew that and included tons of relevant stuff. It contains descriptions of how "large" buildings can be built (large by medieval standards, of course). Including textual descriptions of plans for things like churches. It contains details of how to make agriculture work, when to sow, when to harvest, when to switch between grain and animals, when to ... to make land productive. We still use the 7-year land rotation rule on today's farms.

Given that the bible clearly was meant to be a sort of "civilization in a single (if massive) book", it makes sense that intuitive descriptions for pi would be one of the things found in there. Perhaps the same is true for the vedas ?

Maybe I'm putting the horse before the cart here. The situation could be reversed as well. Assuming a religion gets of the ground at all, it's survival depends on how well it's subjects do. So it's only natural that the religions that grow huge in some way things like the (approximate) value of Pi, and stuff like making agriculture work. And like in the real world you have different flavors of survival. Building, breeding, growing and defense clearly weighed heavily on the bible, vedas and buddhist texts (all of those books, for example, heavily favor not counterattacking an enemy that comes and fights for plunder, merely to let plunder run out and let the attacker starve), whereas conquest, plundering and looting predominate, for example, the quran or the original mongol religion (those religions focus on things like plunder, remaining mobile (e.g. absurd punishments for doing things to horses), and very strict rules about not directly attacking other religions (only their power on the ground). They all have rules about recruiting new cannon fodder (ie. promises of plunder for anyone who joins the religion, making it everyone's duty to recruit new members, ...). Islam actually contains rules that bear a resemblance to a multilevel marketing scheme. If you bring new members, you get a share of their loot for a while). "Growing" religions are vulnerable when they reach a large size, because at some point the borders can't expand while the population keeps growing. "Attacking" religions have the same problem any predator population does : they can only grow by destroying other populations, never by themselves. They survive as tiny inactive pockets, every now and then blowing up exponentially only to die off just as fast soon after, leaving enormous devastation (to read about this in nature, read about the history of wildlife management, or about what happened in Australia, or for a less extreme example American national parks).

Maybe we should just look at religions as just another form of life. Not "really" alive, but certainly making a huge difference in the world. (Yes, I've read Jared Diamond's books).

If a religion did not imitate a real-world survival technique it simply wouldn't survive. So there probably have been a lot of alternate versions, just almost no surviving ones.