Description of Problem:
Trying to add a directory which does not have execute permisssions,
hangs file roller. The error message displayed before the hang also
needs a fix.

Steps to reproduce the problem:
1. Click on Programs->Accessories->Archive Files
2. Click on 'New'
3. Give any name to the archive and click on 'New'
4. Click on 'Add'
5. Double click on 'Filesystem'
6. Double click on 'tmp'
7. Double click on 'gconfd-root'
8. Close the window by clicking on the 'X' button of the window. Do not
   click on 'Cancel'
9. An error message 'You dont have right permissions to read files from
   folder "%s" '
10. Click on 'Cancel'

Actual Results:
File roller hangs.

Expected Results:
- File roller should not hang. 
- Error message should pop up immediately when trying to access 
  directories with insufficient perms.
- The error message needs a fix.

How often does this happen? 
Always