SQL Server 2005 Linked Server Error - "data that does not match expected data length"

Ran into this error today while trying to do an import. The scenario is that I had a linked server to an MS Access database. After a bit of search and using the force, I discovered that the problem was due to fields set to an empty string as opposed to Null. Running a quick update query that set the given column value to Null where its length was less than one did the trick.