Am I completely off the track and missing something obvious?

You can't find it on ActiveState's ppm repo cause it comes with ActivePerl.

Is it worth uninstalling 5.10 and reverting to 5.8?

I have 6 version of Perl on my machine, including two builds of 5.8.8. Just install them in different directories.

Should I just do it on my home computer under linux?

Win32::OLE won't run under linux. As far as I know, it'll run under a Windows emulator under linux, but that won't help since you'd still need to build or download the module under Windows.

Update: Answered two more questions.