Verbatim has a satisfaction guarantee. You can visit the website for details. Supposedly, they will replace any faulty media. You're just gonna' have to try them out. We've all had to do this. Welcome to the world of writable optical media--it's always a crap-shoot the first time you try a new line of media.
Scan them first with CDSpeed2000 or ADVDInfo to find out what speed is best for burning them (check the sticky's up top this forum list for the details and how-to's).
If it ain't broke don't try to fix it! But, hell if you can tweak that bastard just a little bit more....hehehe.