I got the same error with every file I tried to compile and after few frustrating hours I found a workaround.
I'm using OSX 10.6 and I had installed Lua 5.1.4 from MacPorts. At first I thought that something was wrong with my ports install and I removed the MacPorts install and downloaded new 5.1.4 binaries from Lua.org. The luac from those binaries produced the same "Info.lua: bad header in pre-compiled chunk." error (the bad header error came in all compiled files).
I found some posts in other forums mentioning encoding / locale settings causing this type of problem. I opened up my Windows XP (virtual machine) and downloaded the Lua binaries from Lua.org to the windows machine. After compiling the plugins lua-files in windows it worked without a flaw in Windows and Mac.
Something sucks in Luac 5.1.4 + OSX 10.6 + Lightroom 2.8 combination when trying to compile plugins.
So no real answers and only a bad workaround for Mac users....
It's 5.1 AFAIK.
I usually dupe the folder then overwrite each file. To be more precise I copy the directory listing into a text file and create all the compile commands there and then paste the whole thing into the CLI.
It's 5.1.2 to be precise ... same version we've used across all versions of Lightroom so far. That said, I don't think it matters which of the 5.1.x versions you use when compiling.
You should stay away from the Lua 5.2 prerelease versions as far as Lightroom is concerned. There are some new language features and I would not expect the byte codes from one to work in the other.