CLSQL fails to compile on LispWorks 6?

My apologies in advance for what may be a simple compilation problem,
but I think CLSQL is broken under LispWorks 6.0 (Enterprise Edition).
Has anybody else seen this, or developed a patch/workaround?

Specifically, it looks as though MP:WITHOUT-PREEMPTION has been
deprecated (see
http://www.lispworks.com/documentation/lw60/RNIG/html/readme-293.htm#marker-924998)
and thus ASDF fails as shown below:

CL-USER 25 > (asdf:oos 'asdf:load-op 'clsql)
;;; Compiling file z:\lisp\share\clsql-4.2.0\sql\sequences.lisp ...
;;; Safety = 3, Speed = 1, Space = 1, Float = 1, Interruptible = 1
;;; Compilation speed = 1, Debug = 2, Fixnum safety = 3
;;; Source level debugging is on
;;; Source file recording is  on
;;; Cross referencing is on
; (TOP-LEVEL-FORM 0)
; (TOP-LEVEL-FORM 1)
; (DEFCLASS CLSQL-SYS::GENERIC-DATABASE)
; CLSQL-SYS::%SEQUENCE-NAME-TO-TABLE
; CLSQL-SYS::%TABLE-NAME-TO-SEQUENCE-NAME
; (METHOD CLSQL-SYS:DATABASE-CREATE-SEQUENCE (T T))
; (METHOD CLSQL-SYS:DATABASE-DROP-SEQUENCE (T T))
; (METHOD CLSQL-SYS:DATABASE-LIST-SEQUENCES (T))
; (METHOD CLSQL-SYS:DATABASE-SET-SEQUENCE-POSITION (T T T))

**++++ Error in (METHOD CLSQL-SYS:DATABASE-SEQUENCE-NEXT (T T)):
 WITHOUT-PREEMPTION is used

**++++ Error in (METHOD CLSQL-SYS:DATABASE-SEQUENCE-LAST (T T)):
 WITHOUT-PREEMPTION is used
;; Processing Cross Reference Information
; *** 2 errors detected, no fasl file produced.

Thanks,
Kev