Your code looks OK from this distance. I'd first suggest trying to output a few characters from your document on STDERR, just to make sure you're really opening the file as you intended. (I think, but I'm not sure, that if the file doesn't exist, Word will treat it as a "New" rather than "Open".)

As for commands you can use, those will not be in the Win32::OLE documents, which only outline how to use the calls to various COM objects. What you're really after is the Word documentation itself. You can translate the VBA calls in the documentation pretty much directly to Perl. You may need to install additional Word documents to get the "Developer's Reference".

HTH