Whenever runtime problems occur, take a look at Zoidcom's logging output. It might contain hints to what is going wrong. How to enable logging is described in Layer 1: Base Initialization.
Deleting ZCom_BitStream objects
After sending a ZCom_BitStream object, don't delete it. Zoidcom assumes ownership of the streams and will delete them automatically after use.
Replicators And Memory Overwrites
When registering integer data for replication in a ZCom_Node, make sure to only register zU32 types or anything else with at least the same size. When Zoidcom receives updates for such data, 4 bytes will be written to the registered variable. If you register like that:
Use correct port
When connecting to a Zoidcom host, don't forget to specify the target port in the address string (e.g. "192.168.5.44:9931").
Check port forwarding
When connecting to a server behind a router, the router needs to have the target server UDP port forwarded.
Make sure that no firewall software is running (including Window's builtin one) or open up the used ports for UDP traffic.
LAN Discovery does not work
On Unix systems, normal users sometimes are not allowed to use broadcasting on sockets. Check permissions when LAN discovery does not work. The logfile should complain about this problem, too.