The problem is that the validation rule is firing when the field is blank.... I previously had "Renewal_Participation_Audit_Contact <> null" but that did not work either... I am using "AND" so shouldnt the validation rule not fire if the field is null? Here is the validation...
AND(Renewal_Participation_Audit_Contact__r.AccountId <> Id, Renewal_Participation_Audit_Contact__r.AccountId <>'0017000000bZSfW',Renewal_Participation_Audit_Contact__r.AccountId <> null, Len(Renewal_Participation_Audit_Contact__c)>0)
Thanks!!
2 answers

Try using NOT(ISNULL) instead of LEN for Renewal_Participation_Audit_Contact__c
AND(
Renewal_Participation_Audit_Contact__r.AccountId <> Id, Renewal_Participation_Audit_Contact__r.AccountId <>'0017000000bZSfW',
Renewal_Participation_Audit_Contact__r.AccountId <> null,
NOT(ISNULL(Renewal_Participation_Audit_Contact__c))
)