Are there any problems if I run FM5server and FM9server in the same network? Any documentations or refrences will be great.

Dont run it on the same box.

Yes, there can be.

First, if there are external WAN connections through a firewall, you have to decide how to manage the port 5003 forwarding. The best approach is to have two different public IP addresses, one for each version. Then forward ports to the NAT address of the appropriate server.

Additionally, there have been some reports of network traffic slowing for FileMaker caused by running both versions. There were earlier on in the Server 7 era. However this might still occur.

As noted, do not even attempt to run these on the same server.

Finally, remember that the file formats for .fp5 and .fp7 are different and are not compatible.

HTH

Steven