G4 (mail1.3.11 OS 10.3.9) to G5 (mail 2.1, OS 10.4.9) mail transfer

Question

Trying to transfer my mail messages from my old g4 to my new G5, When I follow the directions quoted here in the forums, no luck.
"database in ~/Library/Mail. Copying this directory along with the preferences file at ~/Library/Preferences/com.apple.Mail will transfer your mail."
Old system - G4 (mail1.3.11 OS 10.3.9)
New System - G5 (mail 2.1, OS 10.4.9)
All I get is my list of mailboxes with no messages in them, and my inbox is completely empty as well?
Any ideas? I couldn't use the migration assistant cause the hard drive in my old G4 wouldn't boot up in firewire mode since it was a replacement drive not hooked up to BUS 0...
mac Mac OS X (10.4.9) g4/pc
mac Mac OS X (10.4.9) g4/pc
mac Mac OS X (10.4.9) g4/pc
mac   Mac OS X (10.4.9)   g4/pc

Answer 1

Do you want to merge the mail currently stored on the G4 with what may already be stored on the G5, or do you want to replace what you have on the G5 with what you have on the G4?
If the former, you must do File > Import Mailboxes, as Allan has suggested.
If the latter, however, you should certainly be able to transfer your mail from a computer running Mac OS X 10.3 to another running Mac OS X 10.4 (but not the other way around) by copying ~/Library/Preferences/com.apple.mail.plist and the entire ~/Library/Mail folder. Mail should convert automatically the mailboxes to the new format in place, which may or may not work as expected, but that’s another story...
The thing is, what you’ve described would indicate that you’ve done something wrong, such as copying the contents of the old computer’s ~/Library/Mail/ folder to the new computer, which won’t work if you’ve already used Mail on the new computer and an Envelope Index is already present in ~/Library/Mail/. You must replace the entire ~/Library/Mail folder itself — unless you want to merge the contents of both ~/Library/Mail/ folders, in which case you must do File > Import Mailboxes instead.
In order to avoid potential permission issues, copy the files operating on the destination computer and while logged in as the user that’s going to use them. Also, be sure Mail isn’t running on either computer while doing that.
In order to avoid accidentally losing any data, instead of overwriting the ~/Library/Mail folder on the destination right away, move it to the Desktop before transferring the files, and delete it only after making sure that you don’t miss anything.