1.5.40 breaks make web-doc

[Chris Jackson]

Calculating column positions... [3][5]
paper output to `lily-448640368.tex'...
writing header field `texidoc' to `lily-448640368.texidoc'...
warning: Can't find property type-check for `position' (backend-type?).
Perhaps you made a typing error? Doing assignment anyway.
<snip>
Backtrace:
0* [New_beam::after_line_breaking #<Grob Beam >]
1* [New_beam::quantise_position #<Grob Beam >]

ERROR: In procedure New_beam::quantise_position:
ERROR: Wrong type argument: #f
Error command exited with value 512

  Exiting ... 

Traceback (most recent call last):
  File ".././scripts/lilypond-book.py", line 1363, in ?
  File ".././scripts/lilypond-book.py", line 1283, in do_file
  File ".././scripts/lilypond-book.py", line 1056, in compile_all_files
  File ".././scripts/lilypond-book.py", line 982, in system
  File ".././scripts/lilypond-book.py", line 551, in error
Exiting.
make[1]: *** [out-www/regression-test.texi] Error 1
rm out-www/index.texi
make[1]: Leaving directory
`/home/chris/lilyhack/releases/lilypond-1.5.40/Documentation'
make: *** [web-doc] Error 2


-- 
chris