Problem displaying Email content

My wife's old G3 iMac recently started having a problem displaying the Email contents. If she opens the Mail program from scratch it works OK. If you then close the Mail window without quiting it comes up showing the following:

The message from (Emailers name) <Emailers address> concerning “Fwd: bla bla bla” has not been downloaded from the server. You need to take this account online in order to download it.

All Emails show the same except for Email addresses and subject which I obviously left out.

If you go back and Quit Mail again when you start it next time the Email contents are normal again. So closing the Mail window without Quiting the program causes the issue.

The only thing I could think of doing is repairing permissions which didn't help.

Any ideas

Your best bet is to:
Quit Mail
Drag the Mail Folder from your Library out onto the DeskTop.
Make a New Account.
Then Import the Old Mail from the File Menu.

G3, Time to get a new iMac.

I may give your idea a try. My wife is touchy about me messing with her computer. Is there any possibility of losing any Emails if I create a new account? She finds it impossible to get rid of any Emails. I can't convince her otherwise. Listen to this. She has more then 2700 Emails still in her Inbox. She would have more but her original HD failed about a year ago, losing all the old Emails. I installed a new one, but she still won't keep her Inbox cleaned out. I've tried to get her to get a new computer, but she has Zero interest in doing that. As for me I have the latest 21" iMac and a 13" Macbook Pro about 6 months old. I may have to sabotage the old computer and pretend it just bit the dust.

LOL.

Make sure you backup her Mail Folder! before touching it;-) Right Click and Archive. Move it right off to a DVD.

You will also want to Backup and check the contents of Mail Downloads. This shouldn't matter, but best be safe.

The old pre Leopard Mail was very dodgy, especially with large Mailboxes and over Time.
It was our most compelling argument to move people to Leopard or newer.