I'm glad you fix it, but maybe you disabled the original maemo.org catalogs during the transition from Nokia to the Community? Maybe you're still using the mirrors. People here have installed Yappari 0.0.29 through Application Manager with no problems. http://maemo.org/packages/view/yappari/
If your About dialog says 0.0.28 or lower then you installed Yappari when it was still running. Kill it, or reboot your phone.