Hi - wondering if anyone can help.

I have just restored my PC which is running XP using the symantec restore which went great. However when I plugged my USB Verbatim hard drive in to restore my files and settings and point ot the correct file it tells me "The location you specified does not contain stored information. Please type a valid folder path in the edit box?? If you entered a path to a folder on a removable disc, the disk must be in the drive"

I thought I was doing the right thing by using an external HDD and it has created a file  USMt2.USC and it has 1.4GB showing but the system does not recognise it. it is showing as a .DAT file.

Have I done something wrong or am I just being stupid??