You mention you are using a column link. Any reason why your are not using the item settings in the column link settings of the column attributes.
What are you trying to accomplice? What problem are you trying to solve with using the dynamic action?
What kind of report are we talking about? Classic or interactive.
Use apex.oracle.com to show us what you already have.
Thank You Nicolette,
The approach i was using to achieve this functionality was wrong , thank you for your help.
I achieved the required functionality with given code.
Created a link in column of report.
In the Column Link Section, change column target into URL and place the given URL in the URL field.
It solved my problem.