Not quite as explicit as vinyl-junkie's instructions: "Run the sql code in update_db_to_1_8_1.sql and update_db_to_1_8_2.sql to create those tables"
I was also looking for an 'UPGRADE' instruction file in the .zip. Perhaps one could be inserted to save my forehead? And/or include a note in the 'Quick Installation Directions' to "See below for upgrading instructions" This would save a lot of hassle and headaches and blue language.