1st, are you using an Administrator account?
2nd, what happens if you right click the program icon and select "Run as Administrator" from the option list?
File Menu/Project Archiver
What are you selecting Archive Project or Copy Project?
When the Project Archiver dialog is opened:
What do you have in the Project Location field and/or what are you trying to Browse to and put in that field?
The default is:
C:\Users\Owner\My Documents\Adobe\Premiere Elements\11.0
What happens if you try to move forward with the default setting rather than selecting another location. And, what are the locations that you have tried?
Can we assume that you are getting this error message when you try to select a Project Location in the Browse for Folder dialog and try to close out of that dialog?
Are you having any problems saving projects when the Project Archiver is not involved?
We will be watching for your follow up to decide what next.