IIRC (and I haven't used nstcl with ODBC much myself, other than general proof-of-concept--my personal use being limited to Postgres, Solid, Oracle, and SQLite), this was a bug that has been corrected in either nstcl 1.1 or 1.2.
You can grab nstcl 1.2 from nstcl.sourceforge.net.
