Some of you might have encountered, and some of you are yet to encounter it. What is it? It is the oracle's universal installer. In the past, I had been following the oracle's OFA structure, and had seperated my application from one another, under the impressio, that I can manage them independently. So, lately I upgraded my OEM which is under a seperate home, to V2.2. After the upgrade, every thing seem to work fine except the OAS. Started to dig out the cause and couldn't figure it out for the last two weeks. Both me and my oracle support personel, were in a state to loose our brains. Then the oracle support came up with this answer,
"When you install Oracle products on the same box, but different homes, each time you install a product, a list of products and files already installed is kept in the oraInst.loc parameter file. This file is not in the Oracle_Home, but in /var/opt/oracle directory. So anytime you install a new Oracle product it has the ability to read this file and determine what is already on the box. It appears in your situtation that the OEM Universal Installer read this file, and overwrote some of the existing OAS files--even though they are in a different Oracle_Home. There is no relinking these files. The only solution is to re-install OAS and OEM. I'm sure that's not what you wanted to hear. "
So this is why I called "Universal installer UNIVERSAL". So, folks a word of caution be careful when you have more than one product on the same machine (I'm pretty sure many of us would be!) and were to go on an upgrades or installs.