Difficulties byte-compiling very large .el

[Aemon]

I've been working on a project to create an elisp target for the ANTLR
parser-generator. Here's the project page:
http://github.com/aemoncannon/antlr-elisp/tree/experimental

The generated parser for ActionScript 3 is over 30k lines long and
fails to byte-compile with the message:
as3_elispParser.el:31515:33:Error: Invalid character: 256, #o400,
#x100

Here's the source in question: http://aemon.com/file_dump/as3_elispParser.el

I don't think the error is actually related to the content of the
file, as deleting arbitrary chunks seems to make the error go away.

There are lots of "Warning: reference to free variable ...." warnings,
but I understand where those are coming from and I'm not worried about
them.

Bear in mind there are *lots* of macros being expanded. Most of the
forms with the prefix 'a3el' are macros.

Any ideas?