Windows? When I run Makefile.PL for DBD-ODBC-1.41 on Linux, I get the following:
SYSTEM DATA SOURCES: /etc/unixODBC/odbc.ini
FILE DATA SOURCES..: /etc/unixODBC/ODBCDataSources
USER DATA SOURCES..: /home/mb/.odbc.ini
SQLULEN Size.......: 8
SQLLEN Size........: 8
SQLSETPOSIROW Size.: 8
All 64bit sizes.
dbdimp.h has this definition:
SQLLEN RowCount; /* Rows affected by insert, update, delete
* (unreliable for SELECT) */
This member looks like it was the culprit here and somehow ended up as 32bit. The build output of DBD-ODBC should have some clues.