The value supplied for the school level doesn't match the level name in WhippleHill.
For example, if the value for "level_description" in the data import file is "US", but in Schools & Grade Levels, the name of the level is "Upper School", these are not identical and so no match was found. 

No Match:AC_Offer

The name of the Sport Level/Team (course_title) is either mis-spelled or doesn't exist in WhippleHill.  
If the Team does exist in WhippleHill and it is spelled correctly in the data import file, then the Team has not been set-up or offered for the school year+ season (this_duration) identified in the data file. 

No Match:Duration

The value supplied in "this_duration" cannot be found for the School Year+Level supplied in the data import file. Either it doesn't exist yet in Whipplehill or is mis-spelled.
Example:  school creates a Fall term for athletics where Season Name=Fall and Description=Season. However, in the data import file, the value for this_duration=Fall Season.  What should have been supplied is just "Fall" (season name)--not Fall Season.

No Match:Section

The data import will attempt to find the Team based upon the supplied Level+School Year+Duration supplied in the file.  If there are any errors pertaining to these 3 items, then you will always get this error message.  Address any issues with Level, School Year + Duration, then try again and this will typically resolve this error.  However, if the Team hasn't been offered yet for the school year identified, you will need to resolve this first.

No Match:Location

Either the Location name is mis-spelled or doesn't exist in WhippleHill.

No Match:Opponent

Either the Opponent name is mis-spelled or doesn't exist in WhippleHill. 

Multiple Match:Opponent

In WhippleHill, there are more than one opponents with the same name.  So data import doesn't know which one to pick.  Either delete the duplicate Opponent -or- modify one of the opponent names to make them unique.

Multiple Match:Location

In WhippleHill, there are more than one locations with the same name.  So data import doesn't know which one to pick.  Either delete the duplicate Location -or- modify one of the location's names to make them unique.