InfoPath file attachment size limit
It is easy to upload documents to a SharePoint document library using SmartObjects. I recently ran into a problem when attempting to upload large documents that were attached to an InfoPath form via a SmartObject 'Create' method. The request was failing due to the large file size of my file (> 5 MB). The fix lies in either the machine.config file or the web.config file of the MOSS server. You'll need to increase the 'maxRequestLength' value in order to upload larger files. Ex:
<httpRuntime maxRequestLength="8192" />
The Microsoft article is here: http://support.microsoft.com/default.aspx?scid=kb;EN-US;295626