Original file (102 bytes):

(use awful)

(enable-sxml #t)

(define-page (main-page-path)
  (lambda ()
    "Hello there!"))


Testing file-read:
CHICKEN
(c) 2008-2014, The Chicken Team
(c) 2000-2007, Felix L. Winkelmann
Version 4.9.1 (rev b00d73a)
windows-mingw32-x86 [ manyargs dload ptables ]
compiled 2014-04-19 on Cairo (MINGW32_NT-6.1)
#;1> (use posix)
; loading c:/MinGW//lib/chicken/7/posix.import.so ...
; loading library posix ...
#;2> (define fileno (port->fileno (open-input-file "lobby.css")))
#;3> (define read (file-read fileno 95))
#;4> read
("(use awful)\n\n(enable-sxml #t)\n\n(define-page (main-page-path)\n  (lambda ()
\n    \"Hello thero ther" 89)
#;5> (string-length (car read))
95

$ uname -a
Linux ridgewood 3.2.0-4-amd64 #1 SMP Debian 3.2.54-2 x86_64 GNU/Linux

x.scm:
-----
(use posix)
(define fileno (port->fileno (open-input-file "lobby.css")))
(define read (file-read fileno 95))
(pp read)
(pp (string-length (car read)))
-----


$ /usr/local/chicken-4.7.0/bin/csi -ns x.scm 
("(use awful)\n\n(enable-sxml #t)\n\n(define-page (main-page-path)\n  (lambda ()\n    \"Hello there!\"))\n"
 95)
95

-----
$ /usr/local/chicken-4.9.0/bin/csi -ns x.scm 

Error: segmentation violation

        Call history:

        <syntax>          (quote posix)
        <syntax>          (##core#quote posix)
        <syntax>          (import posix)
        <syntax>          (##core#undefined)
        <syntax>          (##core#undefined)
        <eval>    (##sys#load-library (quote posix) #f)
        <syntax>          (define fileno (port->fileno (open-input-file "lobby.css")))
        <syntax>          (##core#set! fileno (port->fileno (open-input-file "lobby.css")))
        <syntax>          (port->fileno (open-input-file "lobby.css"))
        <syntax>          (open-input-file "lobby.css")
        <eval>    (port->fileno (open-input-file "lobby.css"))
        <eval>    (open-input-file "lobby.css")
        <syntax>          (define read (file-read fileno 95))
        <syntax>          (##core#set! read (file-read fileno 95))
        <syntax>          (file-read fileno 95)
        <eval>    (file-read fileno 95) <--
-----

$ /usr/local/chicken-4.9.0/bin/csc x.scm 

Warning: at toplevel:
  assignment of value of type `list' to toplevel variable `read' does not match declared type `(procedure read (#!optional input-port) *)'

Warning: redefinition of standard binding: read


y.scm:
-----
(use posix)
(define fileno (port->fileno (open-input-file "lobby.css")))
(define r (file-read fileno 95))
(pp r)
(pp (string-length (car r)))
-----

$ /usr/local/chicken-4.9.0/bin/csc x.scm 

$ /usr/local/chicken-4.9.0/bin/csi -ns x.scm 
("(use awful)\n\n(enable-sxml #t)\n\n(define-page (main-page-path)\n  (lambda ()\n    \"Hello there!\"))\n"
 95)
95

Same behavior with file-open:

CHICKEN
(c) 2008-2014, The Chicken Team
(c) 2000-2007, Felix L. Winkelmann
Version 4.9.1 (rev a3c7a5a)
windows-mingw32-x86 [ manyargs dload ptables ]
compiled 2014-05-04 on Cairo (MINGW32_NT-6.1)

#;1> (use posix)
; loading C:/MinGW//lib/chicken/7/posix.import.so ...
; loading library posix ...
#;2> (define fd (file-open "lobby.css" open/read))
#;3> fd
3
#;4> (define r (file-read fd 95))
#;5> r
("(use awful)\n\n(enable-sxml #t)\n\n(define-page (main-page-path)\n  (lambda ()
\n    \"Hello thero ther" 89)

However, if we add the binary flag:

CHICKEN
(c) 2008-2014, The Chicken Team
(c) 2000-2007, Felix L. Winkelmann
Version 4.9.1 (rev a3c7a5a)
windows-mingw32-x86 [ manyargs dload ptables ]
compiled 2014-05-04 on Cairo (MINGW32_NT-6.1)

#;1> (use posix)
; loading C:/MinGW//lib/chicken/7/posix.import.so ...
; loading library posix ...
#;2> (define fd (file-open "lobby.css" (+ open/read open/binary)))
#;3> fd
3
#;4> (define r (file-read fd 95))
#;5> r
("(use awful)\r\n\r\n(enable-sxml #t)\r\n\r\n(define-page (main-page-path)\r\n
(lambda ()\r\n    \"Hello ther" 95)