opening in spreadsheet view

opening in spreadsheet view

hi,
when opening our shipping list DB in spreadsheet view (after I filtered the results) I always get a frozen site and an error report:

Line 100088136, row 5189
'J' exists

am in a slight despair here, I promoted your site as a great way of using it in our company but now it seems that I might have to drop that alltogether again due to these instabilities...

let me know what to do. thanks
m.jansen