Depending on the OS you are using, I would check the ODBC connections. I have run into similar types of errors if the ODBC is not set up correctly. In windows it's set with the ODBC Data Source Administrator. Also I found a link to a similar discussion using google.

www.issociate.de/board/post/172801/NLS_issues_if_using_DBD::Oracle_from_mod_perl2.html