I thought the fix would be an easy template change, but I was wrong.

The file to be fixed is ./includes/modules/shipping/perweightunit.php

Just search for "determin" and add an e. It's in the middle of SQL commands to populate the table, so just this code fix will not fix it in people's installations. Fixing the entry in the DB tables is beyond the scope of this bug report. ;-)

For the record, there are some occurrences of "determin" in comments in other files. For those files, here is the result of my grep (including line numbers for your spell-correction pleasure):

./includes/functions/functions_prices.php:803:// this gets the discount amount this does not determin when to apply the discount
./includes/functions/functions_prices.php:895:// this gets the discount amount this does not determin when to apply the discount
./includes/functions/functions_lookups.php:233: // don't include READONLY attributes to determin if attributes must be selected to add to cart
./admin/includes/functions/general.php:1832: // don't include READONLY attributes to determin if attributes must be selected to add to cart
./admin/includes/functions/functions_prices.php:783:// this gets the discount amount this does not determin when to apply the discount
./admin/includes/functions/functions_prices.php:875:// this gets the discount amount this does not determin when to apply the discount