The script uses a library that provides a 'JDBC to ODBC bridge', however as you may know, ODBC is a Windows technology/implementation, and even if you have the 'bridge' classes available to you (up to / including JDK 1.7), depending on your platform you may not have (or may not be able to have) the other drivers and elements in place to be able to make calls to the ODBC driver platform. There are a number of references in Google to those difficulties in opening Excel/Access/etc. files using this bridge on unix platforms due to this.
Although I'm not having direct experience of using this library, I would also suspect that the location of the (Excel) file is going to be subject to the limitations of the ODBC driver, and I have not heard of any ODBC drivers for Office document file formats that would directly open a file from an FTP source - though you could consider using / investigating the ftp GEL library calls in order to get the file moved locally and then open it as normal.
That said, I would agree with Dave_3.0 in this post that other approaches to the solution would be prefered: https://communities.ca.com/message/241823128#241823128
You also need to be aware that use of the Java-provided JDBC to ODBC bridge is being removed in Java 8 and so any solution using this would not work/last for very long: JDBC-ODBC Bridge
Status of the JDBC-ODBC Bridge
The JDBC-ODBC Bridge should be considered a transitional solution; it will be removed in JDK 8. In addition, Oracle does not support the JDBC-ODBC Bridge. Oracle recommends that you use JDBC drivers provided by the vendor of your database instead of the JDBC-ODBC Bridge.