Imagine if someone kills the InfoPath server, and you have to get the InfoPath from the Live and then do maintenance.
First problem is that the InfoPath still wants to point to the original server.
You can fix this by renaming the .xsn to .cab, and extracting the files. open the manifest file, reset the URLS to whatever the new server is.
Then you need to turn it back into an xsn. To this, download cab maker.
In Cab Maker, create a .cab file. rename the .cab to .xsn and viola, is InfoPath again.
See http://support.microsoft.com/kb/176810 on how to make a cab
Rename edit etc