Make sure you are doing an MGRSTART at the server (which does a BSTART).
Here's the documentation for the error:
(http://www.pervasive.com/library/docs/psql/870/code_msg/code_msg-3-072.html)
BTCPCOM-21: A TCP/IP NetDBgethostbyname() error (nn) has occurred
An error occurred during a TCP/IP-level NetDBgethostbyname operation. Refer to your operating system documentation for the definition of the error value. Retry the operation again. If the error persists, contact Technical Support at Pervasive Software.