Cannot Access Networked Disk

Using the latest version of Acronis True Image Home 10, and Windows XP SP3, I just added a Belkin Router on my system, which gives me the ability to plug a disk directly into a USB port on the router and have it come up as a connected device on each pc that is connected to my home network. I can successfully use it to back up my computer on the drive that contains the router and is connected through an ethernet cable, but my wife's pc is connected wirelessly to the router. The drive attached to the Belkin router is recognized by her pc, listed under her My Computer Icon, and accessibel by Windows on her pc, but Acronis gives me an error message when I select it to place my backup on the networked drive. The message says: YOU HAVE SELECTED A REMOTE RESOURCE AND HAVE NOT SPECIFIED CREDENTIALS FOR IT. DO YOU WANT TO CONTINUE?" followed by more cauthionary notes that I may not be able to access it later, blah, blah, blah. When I proceed, the backup job bombs out saying that the backup set may be corruped, etc. I read up on specifying credentials, but it asks me for a user name and password under the utilities section on authorizing another disk, and put in a password and username, but get the same message. I also noticed that if I ignored the message the backup, even before it fails, seems to take forever. Is the nature of a home wireless network so slow that it should take me five to six hours for a 70 Gig backup across the network, assuming I can get Acronis to recognize the disk. Any help would be greatly appreciated. Thanks in advance.