As you may know, the Oracle forms protocol is based on graphical components. So even if the applications are the same, you have to make sure that you will have the exact same windows that will be displayed on the different applications logging with different users.
For example, if a new pop-up appears on one application and not on the one where you recorded your script, then your script will fail.
Other possible issue that you did not mention is if you handled dynamic parameters in your script. It can be the root cause of your replaying issue.
Most of the time, you have to handle dynamic parameters that usually appear on the first HTML requests even before the Oracle forms part.
Some of the parameters may still be related to the old environment.