Perhaps FM doesnt support the LONG type. I dont even think Oracle really supports it anymore either. If you have access to your Oracle backend, perhaps you can try a LOB type.
What happens if you try to do an FileMaker ODBC import instead?
I thought that if FM does not support a type, it brings it in as text, which would work fine in this case. But instead it does not even show the column as being available.
I really do not have the ability to change the Oracle backend. It is a pretty closed application.
I can do a FileMake ODBC import and that brings in the Long data type without any problems.