you have badnodes you want to add? open up the badNodes.xml file in your gatherbuddy root folder (open it with notepad or some other text editor). you'll want to add your badnodes in the same format.
<nodesBlacklist>
<bad_location><name>Titanium Vein</name><waypoint>7808.346 -82.07845 880.2682</waypoint><comment>Underground node: 1/9/2010 4:16:36 PM </comment></bad_location>
<bad_location><name>Iron Deposit</name><waypoint>-7104.977 -2640.138 264.9817</waypoint><comment>Automatic blacklist during manouver loop 8/22/2009 11:16:02 PM </comment></bad_location>
</nodesBlacklist>
hope that helps.
if you don't have a badnodes.xml file, find one out of the profiles section and download it.