hi Stevieb, thank you for the kind welcome! I should have said I'd seen that issue on SO and done everything recommended there. Here's my path (relevant folders only):
C:\strawberry\perl\bin\;C:\Strawberry\c\bin;C:\Strawberry\perl\site\bin;
And I've added the system variable perl5lib, which has the value:
C:/Strawberry/perl/vendor/lib;C:/Strawberry/perl/vendor/lib/auto;C:/Strawberry/perl/site/lib;C:/Strawberry/perl/lib;
I also created an issue of my own at SO: http://stackoverflow.com/questions/36793878/cant-run-xmllibxml-on-strawberry-perl-invalid-path-in-dynaloader-pm# - as the advice given in the other issue didn't fix it.