Long IF statement in Excel 2007, won't paste

Hello,
I am trying to use data validation in excel 2007...below is the formula I am using to refer to data on a seperate worksheet. I know the formula will work but I cannot get it to paste into the data validation. Is there a character limit? Is there a way to bypass that?
Please help!


=if(b13="Cleanliness of center",cleanliness, if(b13="Ability staff answer questions",ability, if(b13="Comfort of waiting area",comfort, if (b13="Degree of safety and security felt",degree, if(b13="Ease of finding your way around",ease, if(b13="Friendliness of staff",friendliness, if(b13=”Included in treatment decisions”,included, if(b13=”Info about pain control options”, pain, if(b13=”Information about delays”, delays, if(b13=”Information given your family”, family, if(b13=”Informed about delays during visit”,visit, if(b13=”Instructions re home care”,home, if(b13=”Instructions re preparation for T and T”,prep, if(b13=”Our concern for privacy”,privacy, if(b13=”Our sensitivity to your needs”,needs, if(b13=”Response to concerns/complaints”,concerns, if(b13=”Skill of techs/therapists/nurses”,skill, if(b13=”Staff worked together to provide care”,staff, if(b13=”Waiting time in T&T area”,wait,choose)))))))))))))))))))