I'm not running Windows 98 at this time, but you don't need to export anything, or use any special tools. Just save the folder files on eg a CD before reinstalling.
First of all, you need to set Windows to display all files and folders. This is done in Windows Explorer, in the menu View/Settings, if I'm not mistaken.
The files have the extension .dbx. So to make sure you get all files, click Start/Search/Files and folders. Enter this in the filename space and click "Search now":
The search result is all files that exist on your computer, for all profiles (if you have more than one) and both current and obsolete/backups/archives.
These are the files you need to save. If you plan on putting them on a CD and they take up more than 700 MB, use WinZip or a similar program to compress them. The compression rate is often incredible on these files.