The host/port method of defining the server to connect to only works with very recent versions of DBD::Sybase (1.04) and OpenClient (12.5.1 and later). There is an ActiveState binary of 1.04 available at http://www.peppler.org/downloads/ActiveState that you might want to try, although you need to be sure that you have the correct version of OpenClient installed for this to work.

Alternatively - use the "standard" way of defining the server, by using a logical server name and an entry in the interfaces file (sql.ini on Windows).

Michael