Problem changing server IP address from console.

Have you taken a look at the troubleshooting guide cPanel has over here?
Troubleshooting a Recent Installation

 

I recommend checking with on-site data center staff or network engineering personnel as they should know or be able to obtain with absolute certainty the correct network mask, network gateway, broadcast address, and routing configuration to setup on the system.

For reference, the primary IP address and any optional secondary IP addresses are defined in the usual places you would expect on a Linux system; the following details should help to clarify further:

For the primary IP address of your main network interface of the system:
Directory Path: /etc/sysconfig/network-scripts/
Example (where the interface is named "eth0"):
/etc/sysconfig/network-scripts/ifcfg-eth0

The above example file would contain (at minimum) the following relevant entries:

Code:

DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=<ip>
NETMASK=<netmask>
GATEWAY=<gateway>

Note: Replace the <variables> with the actual value needed (without keeping the less-than/greater-than signs).

For optional secondary IP addresses:
File Path: /etc/ips
Example (one on each new line):

Code:

<ip>:<netmask>:<broadcast>

Secondary IP addresses are read from the above file and initialized via the following script:

Code:

# /etc/init.d/ipaliases
Usage: ipaliases {start|stop|restart|reload}