Matt,
When you pack the table it gets erased and for a moment there is no table there with the proper name. That sends the grid into lala land (that's a technical term).
Before you pack you should;
Thisform.grid1.recordsource = ""
Then after the pack;
Thisform.grid1.recordsource = "YourTableAlias"
It is also a good idea to avoid packing tables interactively as it can be a very time consumming operation which your users probably won't appreciate.