> ServerName - localhost

We don't have such property

> PortNumber - 3050

Same here.

> DatabaseName - localhost/3050:c:/mtest/pastest.fdb

try Database instead of DatabaseName, if you're forced to use
DatabaseName, then you have to switch the class to
org.firebirdsql.pool.sun.AppServerConnectionPoolDataSource (see
http://jaybirdwiki.firebirdsql.org/jaybird/doku.php?id=config:sun_app_server
for more details).

Roman