Am I doing this wrong? Passing a node to a panel generates warning.

I'm setting up a website for the school where I teach, and I would like to have a single panel (like this) that I can reuse for each activity that we have at school (soccer, volleyball, student council, marching band...). I pass into the panel via the URL the taxonomy term for the activity and that gets passed to a few views that pull data for that activity. That part works very well.

But I'm also trying to put a node on the panel that is specific to each activity. So, for instance, for football I use the URL http://lincolnlutheran.org/drupal/activities/75/99 where 75 is the taxonomy id and 99 is the node for the football team. This seems to work, but generates a series of warnings on the Panel edit tab. No warnings for the user, just when I'm editing.

Because of that, I'm not at all convinced that I'm doing this the right way. Should I be putting the articles that describe the activity in something other than a node? Should I be including the node in the Panel in some other way? Should I be passing the argument for the node into the Panel by some other means? Is there a way to associate the node with the taxonomy term in a way that I only have to pass in the taxonomy id?

Any thoughts? Here's the warnings I'm getting...

• warning: Invalid argument supplied for foreach() in /home/lincolnl/public_html/drupal/modules/node/node.module on line 504.
• warning: implode() [function.implode]: Bad arguments. in /home/lincolnl/public_html/drupal/modules/node/node.module on line 508.
• user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
  query: SELECT n.nid, n.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM node n INNER JOIN users u ON u.uid = n.uid INNER JOIN node_revisions r ON r.vid = n.vid WHERE in /home/lincolnl/public_html/drupal/includes/database.mysql.inc on line 172.
• warning: Invalid argument supplied for foreach() in /home/lincolnl/public_html/drupal/modules/node/node.module on line 504.
• warning: implode() [function.implode]: Bad arguments. in /home/lincolnl/public_html/drupal/modules/node/node.module on line 508.
• user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
  query: SELECT n.nid, n.vid, n.type, n.status, n.created, n.changed, n.comment, n.promote, n.sticky, r.timestamp AS revision_timestamp, r.title, r.body, r.teaser, r.log, r.format, u.uid, u.name, u.picture, u.data FROM node n INNER JOIN users u ON u.uid = n.uid INNER JOIN node_revisions r ON r.vid = n.vid WHERE in /home/lincolnl/public_html/drupal/includes/database.mysql.inc on line 172.