[tex-live] Install from DVD fails :-(

[Philip TAYLOR]

Dear Colleagues -- Having downloaded and unpacked
"texlive2008-20080822.iso.lzma", unmangled it
using 7-zip, burnt a DVD from the resulting ISO,
compared the DVD contents (twice) with the ISO,
and started an install, I have hit an error :

> Installing: mftinc
> Installing: mftoeps
> Installing: mh
> Tk::Error: Can't open 'F:/TeX/Live/2008/texmf-dist/source/latex/mh/xfrac.dtx': 
> Permission denied
>  TeXLive::TLUtils::copy at tlpkg/TeXLive/TLUtils.pm line 727
>  TeXLive::TLUtils::install_package at tlpkg/TeXLive/TLUtils.pm line 895
>  TeXLive::TLUtils::install_packages at tlpkg/TeXLive/TLUtils.pm line 804
>  main::do_install_packages at G:\install-tl line 901
>  main::do_installation at G:\install-tl line 482
>  main::__ANON__ at tlpkg/installer/install-menu-perltk.pl line 379
>  Tk callback for .frame.frame.frame1.frame.button
>  Tk::__ANON__ at G:\tlpkg\installer\perllib/Tk.pm line 247
>  Tk::Button::butUp at G:\tlpkg\installer\perllib/Tk/Button.pm line 111
>  <ButtonRelease-1>
>  (command bound to event)

Have you any thoughts/suggestions ?

** Phil.