Q: Trying to install Office Mac 2011 on PowerBook G4 with PowerPC processor

You need to get a new or secondhand Intel Mac to run it; PowerPC Macs can't be upgraded to Intel ones.

(68914)

Google is your friend.

You don't need a new processor, you need a new Mac.

Why do you need Office 2011?

Office v.X served me perfectly well for the entire PowerPC era.

Office 2011 system requirements

There are versions of Neo Office, OpenOffice, and LibreOffice that supported PowerPC Macs.  Google Docs and Zoho Docs both do via the web to open Word and Excel files.

You can still get Office 2008 here:

Microsoft Office 2008 Mac Edition For up to 3 Users! For both Intel and G4/G5 PowerPC Macs

I have my three-user set on two Intel Macs and one PPC mac and it runs fine on all three. Office 2008 was the first Mac version with Intel code and the only version with both Intel and PowerPC code.