[OS X TeX] a texdoc problem

[Vic Norton]

I recently bought a new iMac. I have installed MacTeX on it with the latest 
MacTex-2011.mpkg.

Everything is working perfectly except for "texdoc", which doesn't work at all. This is what I see on Terminal:

~$ texdoc
/usr/texbin/texdoc:7: module 'texdoc.main' not found:
	no field package.preload['texdoc.main']
	[kpse lua searcher] file not found: 'texdoc.main'
	[kpse C searcher] file not found: 'texdoc.main'
	[kpse All-in-one searcher] file not found: 'texdoc'

I have no idea what this is all about. My new MacTeX installation is the same as the one I had on my old iMac. As before
   /usr/texbin
is a symbolic link to
   /usr/local/texlive/2011/bin/x86_64-darwin
which contains texdoc, a symbolic link to
   /usr/local/texlive/2011/texmf/scripts/texdoc/texdoc.tlu
There was no 'texdoc.main' anywhere on my old system, and texdoc worked fine there.

Any ideas on how to solve this problem? Thanks for your help.

Regards,

Vic