The solder I had prior to what I linked was rosin-core. I suppose I just took it for granted what I was getting from RadioShack was similar. My options are quite limited - either RadioShack or Walmart. I will see if I can find some flux and get this to work. I appreciate your comments.
The solder I linked does not say it is rosin-core - is this a bad thing or should I pick up some different solder?