InfoPath Dev

there are atleast two ways of doing it, the recommended one is 1) relinking the documents to the library to do so    a) go to document library -> settings -> document library settings -> relink documents to this library and check the documents and click relink selected documents.  

check this.

check attachment

may be you should try for innerxml

yes it is possible, all you need is a data connection to the other list, and before submit using rules and filters check whether the title is present or not

check attachment

 reverse the condition, make less than to greater than..

try this.DataConnections["Main connection"].Execute();  if that doesnt work check this

 then the best thing will be to check the user permissions on the doc library.

use  FileSubmitConnection fc = (FileSubmitConnection)this.DataConnections["Main submit"]; fc.Execute();