Internal Error while Importing Mailbox

I keep getting the error message:

Internal Error while Importing Mailbox
OSError: error 12 (Cannot allocate memory) for file: /Users/tcouture/Library/Mail/Mailboxes/_Archive/$2008.mbox/Messages

While trying to import about 19,000 messages from a mailbox in mail.app. I already imported about 100,000 messages from other mailboxes but this one keeps failing. It is 64K messages and was giving me the error so I started importing in smaller chunks. The first 30K or so went in OK. But I can’t seem to get the 2nd half of the mbox in.

Currently running 1.4.14 on Snow Leopard but I was getting the same error with Leopard. I have MailTags, Mail Act-On and SpamSieve installed (all with the latest updates).

Any suggestion on how to get around this is appreciated.

Thanks.

Instead of selecting smaller chunks within that mailbox, please try moving some of the messages to a different mailbox. Then import the two (now smaller) mailboxes one at a time.