This might save you some time if you happen to run into it.
Was getting file error 12 on an object instantiation and I wasn't looking for this issue because the object is a file wrapper. After eliminating the file as perpetrator, while I was expecting a 92 type error, I wasn't expecting this as I wouldn't have thought it possible. (The mistake obviously!

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In the Class Def, one of the functions had a trailing comma in the arguments as shown below.
FUNCTION FieldByIndexList(KeyStart$,KeyEnd$,Where$,KeyNo,FieldIdx,FieldDelimiter$,)FIELD_BY_INDEX_LIST
This did not throw a line error in the *IT or on a load list in version 2017, only on instantiation.