I installed Oracle Apps R12 as per the tutorials on this website on my laptop and managed to login with sysadmin/sysadmin. At the same time, I have Oracle 11i Apps Vision Demo installed on my desktop computer which was Up and Running, both laptop and desktop computer being in the same room.
The desktop computer is both LAN and Wirelessly connected to the Internet and my laptop is wirelessly connected.

Just few days after I installed the working Oracle Apps R12 on the laptop, I was not able to login any longer to both the Oracle Apps R12 and Oracle Apps 11i.
On inspection, I noticed that the IP address on the Guess machine (Oracle Enterprise Linux) which I used to connect to Oracle Apps R12 from the Host machine (Windows XP) has changed (has been messed up) from what I used, 192.168.1.4 to 192.168.1.5
A friend I has introduced to www.handsonerp.com have the same IP address issues which has messed up his Oracle Apps installed.

By instead installing VMware Workstation, or VMware Server but without enabling “Bridged” connection would solve the problem? Please help, as this would also allow me to help other people I would introduce to www.handsonerp.com, who cannot afford to pay for the “Practice Server”. Thank you.

Why dont you assign a static IP rather than using dynamic one.

Launch this tool:

/usr/sbin/system-config-network

Assign a static ip e.g. 192.168.1.20
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.1.1

Restart your network.

Thank you, I will try this.

When I have the problem (IP address messed up), I formatted the Hard Disk Drive and installed a fresh Windows XP. So, now I am going to install VMware Server, then Enterprise Linux, then Oracle Apps R12. Could the connection problem be solved in the installation of the VMware Server, by choosing not to enable "Bridged" connection and still have Oracle Apps R12 work, when it is install? Instead of installing Oracle Apps R12 and then run the script you have proposed?
Thank you.

As far as I know Bridged works just fine.
You can try bridge connection first and then enforce static IP by running the command I gave you.
You can always change your network from bridged to NAT even after installing OS. Simply turn off the machine and change your network settings and turn on the machine again.