weird error engraving two files with 2.23.14

[Federico Bruni]

Hi folks

I've recently used convert-ly to update my private music sheet library 
and test version 2.23.14 (official binaries).
Two files are failing with the same error message:

Drawing systems...
Converting to `foo.pdf'...
warning: `(gs -q -dNODISPLAY -dNOSAFER -dNOPAUSE -dBATCH 
-dAutoRotatePages=/None -dPrinted=false /tmp/lilypond-tmp-9384021)' 
failed (256)

/var/home/fede/.local/lilypond/lilypond-2.23.14/share/lilypond/2.23.14/ly/init.ly:65:2: 
error: Guile signaled an error for the expression beginning here
#
(let ((book-handler (if (defined? 'default-toplevel-book-handler)
Throw to key `ly-file-failed' with args `()'.


Any idea about the cause? I'm using a different font for tablature 
numbers, but commenting that line still triggers this error.
These two files are copyrighted and I can't share them here, but I will 
send privately to anyone interested in debugging this issue.

Thanks
Federico

PS
Here's the --verbose log:

GPL Ghostscript 9.56.1 (2022-04-04)
Copyright (C) 2022 Artifex Software, Inc. All rights reserved.
This software is supplied under the GNU AGPLv3 and comes with NO 
WARRANTY:
see the file COPYING for details.
Querying operating system for font files...
Can't find (or can't open) font file %rom%Resource/Font/%rom%Resou.
Can't find (or can't open) font file Arial-Bold.
Didn't find this font on the system!
Substituting font Helvetica-Bold for Arial-Bold.
Can't find (or can't open) font file %rom%Resource/Font/%rom%Resource/F.
Can't find (or can't open) font file NimbusSans-Bold.
Can't find (or can't open) font file %rom%Resource/Font/%rom%Resource/F.
Can't find (or can't open) font file NimbusSans-Bold.
Didn't find this font on the system!
Unable to substitute for font.
Error: /invalidfont in findfont
Operand stack:
  Arial-Bold
Execution stack:
  %interp_exit .runexec2 --nostringval-- .findfontop --nostringval-- 2 
%stopped_push --nostringval-- .findfontop .findfontop false 1 
%stopped_push 1974 1 3 %oparray_pop 1973 1 3 %oparray_pop 1961 1 3 
%oparray_pop 1817 1 3 %oparray_pop --nostringval-- %errorexec_pop 
.runexec2 --nostringval-- .findfontop --nostringval-- 2 %stopped_push 
--nostringval-- 1974 1 3 %oparray_pop 1973 1 3 %oparray_pop 1961 1 3 
%oparray_pop 1817 1 3 %oparray_pop --nostringval-- %errorexec_pop 
.runexec2 --nostringval-- .findfontop --nostringval-- 2 %stopped_push 
--nostringval-- 1909 1 3 %oparray_pop
Dictionary stack:
  --dict:761/1123(ro)(G)-- --dict:0/20(G)-- --dict:115/200(L)--
Current allocation mode is local
Last OS error: Permission denied
Current file position is 915685
GPL Ghostscript 9.56.1: Unrecoverable error, exit code 1
warning: `(gs -dNODISPLAY -dNOSAFER -dNOPAUSE -dBATCH 
-dAutoRotatePages=/None -dPrinted=false /tmp/lilypond-tmp-2513976)' 
failed (256)

/var/home/fede/.local/lilypond/lilypond-2.23.14/share/lilypond/2.23.14/ly/init.ly:65:2: 
error: Guile signaled an error for the expression beginning here
#
(let ((book-handler (if (defined? 'default-toplevel-book-handler)
         14 #
In 
/home/lily/lilypond-2.23.14/release/binaries/lilypond/build/out/share/lilypond/current/scm/lily/lily.scm:
  876:16 13 (lilypond-main _)
   905:4 12 (lilypond-all _)
In srfi/srfi-1.scm:
   640:9 11 (for-each #<procedure 7f6982e60180 at /home/lily/lilyp?> ?)
In 
/home/lily/lilypond-2.23.14/release/binaries/lilypond/build/out/share/lilypond/current/scm/lily/lily.scm:
   915:9 10 (_ _)
In ice-9/boot-9.scm:
   829:9 9 (catch _ _ #<procedure 7f6982e90d40 at /home/lily/lily?> ?)
In unknown file:
          8 (ly:parse-file "Close-to-Heaven.ly")
          7 (apply-smob/1 #<catch-closure 7f6983417a20>)
          6 (ly:book-process #<Book> #< Output_def> #< Output_def> #)
In 
/home/lily/lilypond-2.23.14/release/binaries/lilypond/build/out/share/lilypond/current/scm/lily/backend-library.scm:
   319:4 5 (postprocess-output #< Output_def> #<directory (lily f?> ?)
In srfi/srfi-1.scm:
   640:9 4 (for-each #<procedure 7f69834725c0 at /home/lily/lilyp?> ?)
In 
/home/lily/lilypond-2.23.14/release/binaries/lilypond/build/out/share/lilypond/current/scm/lily/backend-library.scm:
   139:4 3 (postscript->pdf _ _ _ _ #f)
    57:4 2 (ly:gs-cli _ _)
In ice-9/boot-9.scm:
  751:25 1 (dispatch-exception 0 ly-file-failed ())
In unknown file:
          0 (apply-smob/1 #<catch-closure 7f69834179e0> #)
Throw to key `ly-file-failed' with args `()'.