CaseWare Template Packager showing error while adding some new information into files

I have some files already written and I tried adding some new information on one of the files. When I tried to open it and write the following message appeared. I have to specify that I am using Windows XP Professional with Microsoft 2007. Can anyone please tell me how can I solve this problem?
CaseWare Template Packager
File write error. You may not have sufficient permissions to write to the
destination folder, or the current file already exists but cannot be
overwritten.
OK
