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Undefined subroutine &main::UpdateHTML_blib called at -e line 1.
Aaah ... it comes back to me now (with the help of Mr. Google). You would have had exactly the same problem with nmake - and removing Perl\site\lib\ActivePerl will fix that problem, though there may be other issues that need to be dealt with. Build 819 does not have Perl\site\lib\ActivePerl, but earlier builds do. When you install 819 over the top of an earlier build, Perl\site\lib\ActivePerl from that earlier build remains in place - and will be found before 819's Perl\lib\ActivePerl. In this particular instance, the wrong version of DocTools.pm is being loaded.
Here's a posting from Jan Dubois on the same issue (raised elsewhere):
-- quote --
I assume you installed AP819 on top of a previous ActivePerl installation. This is a problem because 819 has all bundled modules installed in the lib tree and not in the site/lib tree. It also changes the order of entries in @INC to put site/lib in front of lib. This allows you to update bundled modules with the new PPM4 and have those new modules override the old ones in lib. If you install on top of an older ActivePerl, then you will have old module versions in site/lib that now shadow the new entries in lib. It would be best to do a clean install of AP819.
-- end quote --
I think this is an issue that relates only to build 819 - with build 820 onwards, attempting to install over the top of a pre-819 build is detected and disallowed.