Hello,
topic title states my problem completely, some details:
- I use emacs compiled from bzr trunk (revno 114606) on my system:
  Archlinux x86_64 with gcc 4.8.1 and make 4.0;
- org-mode: 8.2.1-86-gbe3dad.

This is excert from make log:
#+BEGIN_EXAMPLE
...
Compiling
/home/vladimir/buildpkg/emacs-org-mode/src/org-mode/lisp/ox-publish.el...

In toplevel form:
ox-publish.el:887:1:Error: Multiple args to , are not supported: (\, (\`
(when (quote (\, force)) (org-publish-remove-all-timestamps))) (\` (let
((org-publish-use-timestamps-flag (if (quote (\, force)) nil (\,
org-publish-use-timestamps-flag)))) (org-publish-projects (quote (\,
org-publish-project-alist))))))
...
#+END_EXAMPLE

Full log of make work is attached.

I don't know the reason of this problem because the last change to
'ox-publish.el' file was at Sep. 27 but I could swear I was able to
compile it on Oct. 6.

Nevertheless, if I comment line 896:
#+BEGIN_EXAMPLE
	`(when ',force (org-publish-remove-all-timestamps))
#+END_EXAMPLE
then I'm able to compile org-mode successfully.

---
WBR, Vladimir Lomov

-- 
To get something done, a committee should consist of no more than three
persons, two of them absent.