Question about Outlook Express

Hello!
Not expert in MAC, need help in simple issue.

Have MacBoor Air with Intel Core i5 and 5 Gb RAM DDR3. Use MS Office 2011 for MAC 14.3.9. E-mail account configured to work with POP3.  If I selected  checkbox in Account settings in <Download only headers> than Outlook works OK, it sends and receives messages without any problems.
But this is not normal for me, often I' m work in offline mode without access to Internet. That' s why I prefer to download (receive) whole messages not only header.
To do it I need to leave empty heckbox in Account settings in <Download only headers>. But if I make this configuration I cannot receive messages, it always fails with error "Not Enough Memory", error code 108.
In Microsoft KB I found this article  http://support.microsoft.com/kb/2535724/en but it not works

Would you kindly help me to fix this issue?

Thanks in advance,
                                Yury.