It is normal to have more than one my documents folder on a computer per user account. Administrator, All Users, Guest and Owner are some of the standard names.
I am not sure about the path already being in use... Is that a message that the program tells you or does it seem to be a windows error?
One thing you could try is rebooting the PC. (Standard answer I know...) But the reason I say it this time is because if you switch users in Windows XP, it doesn't always close out the other user completely so some files stay "open". When you reboot, Windows shuts down and closes everything. Then you can log back into Windows and then you may be able to get to the file or path you need. Something to try which may or may solve the issue.
If that doesn't work, you will have to get a little more technical and copy contents of folders around. Fairly simple when you know where to look.
1. Click on Start, there should be name at the top of the menu, make a note of it.
2. Click on Start, click on my computer, then double click Local Disk (usually C:), we are looking for the folder "Documents and Settings"
3. When you click on that it will list all of the users folders on your PC.
4. Look for the folder named the same name you made a note of in step 1.
5. Double click that folder, in that folder double click the folder named Username's Documents. (So if the user is Debbie, click on Debbie's Documents.)
Where you should be is the My Documents folder when you login as the username in step 1.
If the card template is there. You may need to re-path the location within the Card program.
If the card template is not there. You will have to go back a few steps to #3 and look through the other users folders, find the template files, and copy them to your folder.
Hopefully that helps... back to work now. :-)