Could be faulty USB port. In Device Manager do the Universal Serial Bus entries show any problem? (Yellow triangle with exclamation mark)
Troubles shooting information was for Windows 98 so folder structure is different on your system which is why you can't find the folders. You could use Windows Explorer and search the C: drive for the file epusbun.
If none of above get new copy of software/drivers from Epson. Try going here
Download drivers and software for XP and re-install