Hi,
The software Distribution folder in Windows XP is a system folder used to store setup information for updates and other programs. Most of the time, you can delete the contents of the folder to free up disk space.
The folder contains information and files necessary for the installation of system updates and downloaded software. These files are often only used once, when the program or update in question is first installed. The folder can cause problems with program installation if the data become damaged or corrupted.
Scan file subfolder contains the scanned images of the document, pictures etc. Every time you scan, a new folder is created and images of the files that are scanned are stored in that folder. You can backup the images that are present in that folder and then remove it from the system.