Oracle Database Discussions

I would like to use the OUI for doing this upgrade. I've been told to upgrade to 10.2.0.1.0 first, and then apply patch p6810189.

The upgrade guide (B14238-02 released on January 2008) on the Oracle site do not make use of the OUI. The upgrade guide insists you must create a new oracle home, but I've been instructed by the vendor for our third party software to select the original oracle home in order to do the upgrade of oracle (and their information pool located within our oracle database).

When I select the currect oracle home in OUI, I get:

Checking for Oracle Home incompatibilities…
Check Complete. The overall result of this check is: Failed <<<<
Problem: Oracle Database 10g Release 2 can only be installed in a new Oracle Home
Recommendation: Choose a new Oracle Home for installing this product.

Any ideas, is there a different upgrade guide I could use in this case (where I'm upgrading the current oracle home?). Should I be using DBUA instead (not sure how actually but could probably RTM)? DBUA suggests creating a new oracle home also though. Or should I go with a different path entirely here?

Thanks in advance!