In /usr/share/gnucash/scm/report.scm:
 420: 17* (set! doc (if template (let* # # # ...) #f))
 420: 18* (if template (let* # # # ...) #f)
 421: 19  (let* (# # # ...) (gnc:html-document-set-style-sheet! doc stylesheet) ...)
 423: 20* [receivables-renderer #]
In unknown file:
   ?: 21  (letrec (#) (let* # # #))
In /usr/share/gnucash/guile-modules/gnucash/report/aging.scm:
    ...
 517: 22  (let* (# # # ...) (gnc:html-document-set-title! document report-title) ...)
 560: 23* (if account (begin (setup-query query account ...) (let* # # ...)) ...)
 561: 24  (begin (setup-query query account ...) (let* (#) (set! work-to-do #) ...))
 564: 25  (let* ((splits #)) (set! work-to-do (length splits)) ...)
 570: 26* [for-each #<procedure #f (split)> (# # # # ...)]
In unknown file:
   ?: 27* [#<procedure #f (split)> #<gw:wcp <gnc:Split*> 0xc6a2c0>]
In /usr/share/gnucash/guile-modules/gnucash/report/aging.scm:
 573: 28* [update-company-hash #(() () () ...) #<gw:wcp <gnc:Split*> 0xc6a2c0> ...]
In unknown file:
   ?: 29  (letrec ((do-update #)) (let* (# # #) (if # #)))
In /usr/share/gnucash/guile-modules/gnucash/report/aging.scm:
    ...
 204: 30  [cons #f ...
 204: 31*  [sprintf "Transactions relating to '%s' contain more than one currency.  This report is not designed to cope with this possibility." ...]
In unknown file:
   ?: 32   (let* (# # #) (apply stdio:iprintf # format ...) (cond # # #))
   ?: 33*  [apply #<procedure stdio:iprintf #> #<procedure #f #> #f]
   ?: 34   [stdio:iprintf #<procedure #f (x)> #f]
     ...
   ?: 35   (let ((pos -1) (fl #) (fc #)) (letrec (# # # # ...) (# args)))
   ?: 36*  [string-length #f]
<unnamed port>: In procedure string-length in expression (string-length format-string):
<unnamed port>: Wrong type argument in position 1 (expecting string): #f