[nikodemus@delirium:~/tmp]
> cat bug1.lisp
(defclass c1 ()
  ())

(defun a-c1 ()
  (load-time-value (make-instance 'c1)))

[nikodemus@delirium:~/tmp]
> lisp -init /dev/null
; Loading #P"/dev/null".
CMU Common Lisp 20c release-20c (20C Unicode), running on delirium
With core: /usr/local/lib/cmucl/lib/lisp-sse2.core
Dumped on: Thu, 2011-11-03 06:58:17+02:00 on gondor.local
See <http://www.cons.org/cmucl/> for support information.
Loaded subsystems:
    Unicode 1.28 with Unicode version 6.0.0
    Python 1.1, target Intel x86/sse2
    CLOS based on Gerd's PCL 2010/03/19 15:19:03
* (load (compile-file "bug1.lisp"))

; Python version 1.1, VM version Intel x86/sse2 on 2011-12-01 13:14:19.
; Compiling: /Users/nikodemus/tmp/bug1.lisp 2011-12-01 13:13:33

; Compiling Load Time Value of (PCL::ENSURE-CTOR '(PCL::CTOR C1) 'C1 ...):
; Compiling Load Time Value of (MAKE-INSTANCE 'C1):
; Converted A-C1.
; Compiling DEFUN A-C1:
; Byte Compiling Top-Level Form:

; bug1.sse2f written.
; Compilation finished in 0:00:00.

; Loading #P"/Users/nikodemus/tmp/bug1.sse2f".


Error in function PCL::FIND-CLASS-FROM-CELL:  No class named C1.
   [Condition of type SIMPLE-ERROR]

Restarts:
  0: [CONTINUE] Return NIL from load of #P"/Users/nikodemus/tmp/bug1.sse2f".
  1: [ABORT   ] Return to Top-Level.

Debug  (type H for help)

(PCL::FIND-CLASS-FROM-CELL C1 NIL T)
Source: Error finding source:
Error in function DEBUG::GET-FILE-TOP-LEVEL-FORM:  Source file no longer exists:
  target:pcl/macros.lisp.
0]

Cheers,

 -- Nikodemus