Same with Gryx_Ranger, Halfling_Rogue, Human_Cleric_(combat_favoured) and Human_Warrior_Mage. The Rest opens without any problems!
I'm 100% sure that it wasn't a problem with an old Excel version I used during the time the product was released as I opend all of the sheets. Maybe it is an compatibility issue or a security issue which was addressed by MS in the 2010 version of Excel.
EDIT: It seems that all characters from Allen Maher have this problem (and only these). As fas as I know, Allen made some of the spreadsheets himself, maybe he used different Macros, which are not useable/allowed with the current office. But not sure here.