You have two things to consider here, assuming you are checking the Regular Expression checkbox for a Description Property of an object in your OR.
1. The regex has to be correct (of course).
2. The regex has to uniquely identify only the object you want to identify. If it identifies more than one ojbect in your application, QTP will not handle it well.
One way to test your regex the instant you finish writing it is to click the "Highlight in Application" button in your OR toolbar. If the object flashes in the application, then your regex was good. If it doesn't flash, then you need to refine your regex.
Chances are good that if you post your regex here in this forum, along with the actual value of the property, someone might be able to offer advice on how to refine it - assuming you want that kind of help.
I think that I may be having other problems beyond the regular expression. I ended up removing the regular expression language from my parameter and I still couldn't get OR to recognize the object. I just posted another question about the OR and how it handles objects.
TReddy - I'm glad to know that the OR paramater will support regex. At least I don't have to make major updates to my code to handle all of the different permuatation of attributes that can be handled by a simple regex.
BlakeWalker84120 - I'm using QTP 9.2 and in that version I can't select the regex checkbox if I am using a parameter instead of a constant value for the object description. That was one of the reason for my question.
Thanks for the tip on highlighting after wrting the regex. I also found a regex test site that might be helpful to other people in the group. All you have to do is enter the string and your regex and the site determine if the string should be found using the regex. Here is the site: http://www.zytrax.com/tech/web/regex.htm#experiment.