Corion's hint seems to be the one! Thanks, Corion. Now install progresses to running the tests, but fails at :

'C:\Program' is not recognized as an internal or external command,oper
+able program or batch file.
[download]

Progress : put the C:\Program File\....\nmake.exe string in quotes , in MyConfig.pm file , now installed YAML successfully.

Trying JSON::XS, which throws error :

'pl2bat.bat' is not recognized as an internal or external command,oper
+able program or batch file.
[download]

Trying with bin dir appended to %PATH%

UPDATE: JSON::XS and JSON installed successfully.

Summary : 1. Strawberry perl had set environment variables which affected my instance of perl. 2. MyConfig.pm file isn't set right by default for Windows paths which often contain spaces. Need to put such path strings in quotes. 3. Need to run vcvars32.bat and ensure perl/bin is in %PATH%

Thanks to all monks!

I suppose the string needs to be put in quotes someplace - which place ? Is it in MyConfig.pm file in .cpan ?

Well, I've seen that before in a few , but I don't recall from memory off the top of my head where/what/how

Maybe  cpan[1]> o conf or whatever

Maybe update %userprofile% and other vars to use shortnames if you've got that configured

Maybe patch path in pl2bat ... Re: exec not working?

OTOH, I don't think cpanp will have problem with it, I prefer cpanp