in reply to Pattern Match / Replace without s/

I doubt that InstallAnywhere will give you the full power of perl regular expressions. Since you know the exact line you want, why not just replace it literally? 
Search For:
bla.bla.bla = SomeWindows/Path With/Spaces In/It

Replace With:
bla.bla.bla = SomeWindows/Path\ With/Spaces\ In/It

[download]
You might need to double the "\" characters.

In Section Seekers of Perl Wisdom