vipw: pw_tmp(): Operation not permitted

In 5.2.1-RELEASE:

I get this weird error when i try executing vipw:
[root_at_koti] /home/erik $ vipw
vipw: pw_tmp(): Operation not permitted
[root_at_koti] /home/erik $

And yes, /tmp is mounted as read-write and i dont think there's anything 
wrong in it.
I just installed 5.2.1 about 2 days ago and installed XFree86 and KDE.  
And i dont remember patching the source code and compiling anything 
else, but kernel. And if anyone needs the kernel config or anything else 
i'll be happy to mail it.
I haven't got any weird sysctl setting either.