It occurred to me that Huub wrote in gmane.os.netbsd.ports.x86-64:
>> 
>> Full error please. Considering your flipping back-and-forth between pkgsrc
>> versions, are your packages up to date? What does lintpkgsrc -i say?
>> 
>
> OK, here's the result of lintpkgsrc -i:
>
> MesaLib 	6.4.2nb2 	vs. 	6.4.2nb1
> cairo   	1.2.4nb2     		1.0.4nb1
> fixesproto	3.0.2nb1		3.0.2
> fontconfig	2.4.0nb1		2.3.2nb3
> freetype2	2.2.1nb2		2.2.1
> glitz		0.5.6nb2		0.4.4nb4
> m4		1.4.6			1.4.4
> xdg-dirs	1.4			1.3
> zip		2.32			2.31

These are all potential problems for the future, but it doesn't seem to
make much of a difference; I can reproduce your problem. It seems to have
been caused by the recent security pullup in 2006Q2 a few days ago. Since you
mailed this to the wrong mailinglist, the chance that this will be picked up
automagically is small. Please file a PR, and make sure you include
work/.build.log and work/mozilla/config.log. Also note that your problem
is caused by pullup ticket 1826.

In the mean time, pkgsrc-current's firefox will work, and you could revert
back to the previous version of firefox (1.5.0.5) by doing something like

cvs update -r1.34.2.1 Makefile-firefox.common
cvs update -r1.50.2.1 distinfo

in /usr/pkgsrc/www/firefox, and try rebuilding after that.

However, this will leave you with an outdated (and vulnerable) version of
Firefox, so it may not be what you want.

Either way, I'd really suggest you stop switching back and forth between
pkgsrc releases; it only makes things worse.

-- 
    Martijn van Buul - pino@dohd.org - http://www.stack.nl/~martijnb/
	 Geek code: G--  - Visit OuterSpace: mud.stack.nl 3333
 The most exciting phrase to hear in science, the one that heralds new
discoveries, is not 'Eureka!' (I found it!) but 'That's funny ...' Isaac Asimov