[plt-scheme] 3.99 - extension require changed?

Hi all,

I'm upgrading fluxus to 3.99, and I'm having difficulty resolving binary
extension paths with require - has the way these work changed? (the
trick with 'foo.ss' mapping to 'foo.so') The docs look the same to me:
http://docs.plt-scheme.org/inside/overview.html#(part~20embedding

My extension is here:
../plt/collects/fluxus-015/compiled/native/i386-linux/3m/fluxus-engine.so

and in a script inside ../plt/collects/fluxus-015/ both:

#lang scheme/base
(require fluxus-015/fluxus-engine)

and

(module fluxus mzscheme
  (require "fluxus-engine.ss")

result in:

default-load-handler: cannot open input file:
"/usr/local/lib/plt/collects/fluxus-015/fluxus-engine.ss" (No such file
or directory; errno=2)

as a side issue, I also noticed that putting . in a path results in an
invalid module path - is this intended?

cheers,

dave