r7rs and c-wrapper

Hi,

somehow c-wrapper doesn't work correctly in r7rs mode:

$ gosh -r7
gosh[r7rs.user]> (import (gauche keyword))
gosh[r7rs.user]> (import (c-wrapper))
gosh[r7rs.user]> (c-load "stdio.h" :module #f)
#<undef>
gosh[r7rs.user]> (printf "hello world!\n")
hello world!
13
gosh[r7rs.user]> (c-load "stdio.h")
*** ERROR: improper list not allowed: c-wrapper.sandbox.1
    While compiling: (import c-wrapper.sandbox.1)
Stack Trace:
_______________________________________
  0  (report-error e)
  1  (map ($ (cut regexp-replace-all #/\./ <> "..") $ stringify $) ...
  2  (string-join #:G129 ".")
  3  (library-name->module-name import-set)
        at "/usr/share/gauche-0.98/0.9.14/lib/r7rs-setup.scm":87
  4  (rec (unwrap-syntax import-set))
        at "/usr/share/gauche-0.98/0.9.14/lib/r7rs-setup.scm":88
  5  (proc (car xs))
  6  (apply map f lis lists)
  7  (append-map %transfer-import-spec import-sets)
        at "/usr/share/gauche-0.98/0.9.14/lib/r7rs-setup.scm":60
  8  ((macro-transformer mac) expr cenv)
  9  (call-macro-expander gval program cenv)
 10  (pass1 program cenv)
 11  (thunk)
 12  (eval expr env)
        at "/usr/share/gauche-0.98/0.9.14/lib/gauche/interactive.scm":359
 13  (evaluator exp (vm-current-module))
 14  (with-error-handler (^e (report-error e) #t) (^ () (let loop2 ...

greetings
jens