in reply to Learning about OLE and Win32 with Perl.
Along with the online documentation mentioned above, consider the book you mentioned. I own a copy of "Win32 Perl Programming: The Standard Extensions, 2nd Edition" and carry it in my laptop bag. I looked to confirm that chapter 5 is dedicated to OLE. Of the 65 pages in chapter 5, approximately 7 are dedicated to Events. In addition to OLE there are several other valuable chapters on accessing dll files and working with win32 modules in general.
In Section Seekers of Perl Wisdom