You are using the wrong get function.
getString(columnIndex)→ {string}
Returns a string value of the specified column. getString is used for CHAR and VARCHAR column types. ASCII only, not suitable for strings containing Unicode characters.
getNString(columnIndex)→ {string}
Returns a string value of the specified column. getNString is used for NCHAR, NVARCHAR, SHORTTEXT column types.
I'm not sure why it even worked on SPS 08. It really shouldn't have.
I might point out that if you are on SPS 09, you can use the new database interface which directly returns JSON and doesn't require the use of any type specific get or set functions. This would also avoid your problem.