Hi,
Many times me too faced this problem with some pcs. This is happen because of the limitations of DBX files. see this article from Microsoft
http://support.microsoft.com/kb/903095Here its telling the limit as 2 GB. But most of the time DBX files crash when its reach more than 1GB.
In your case i hope the same ting happend. there is a tool called DBXtract. using this exe, you can extract maximum available .eml files.
download DBXtract from this link
http://www.technibble.com/repair-tool-of-the-week-dbxtract-45/