This is due to a conflict in the attributes. 

If you have 'everydayhero Page' and 'Fundraising Page URL' then delete 'everydayhero Page' and attempt to re-import. This should rename the attribute 'Fundraising Page URL' to 'everydayhero Page' in Config > Attributes > Constituent.

Additionally, ensure the following attributes have the correct format as displayed below (attribute name, data type, table name)

Constituent Attributes:
everydayhero Event Participant - Table - everydayhero Event Participant
everydayhero Team Position - Table - everydayhero Team Position
everydayhero Donor - Yes/No
everydayhero Fundraiser - Yes/No
everydayhero ID - Text
everydayhero Page - Text
everydayhero Team - Text

Gift Attributes:
everydayhero Event Participant - Table - everydayhero Event Participant
everydayhero Donation ID - Number
everydayhero Team - Text