If you are getting a warning when trying to open a file that you are missing plugins, then you are trying to open a file that has been saved in a newer version of ID. You will need a newer version to open it or need it resaved as an .IDML file from a newer version in order to open it in CS4.
Thank you for the advice.
On 10.10.2014 10:00, Larry G. Schneider wrote:
HOW DO I OBTAIN AND INSTALL VARIOUS PLUG-IN'S FOR INDESIGN CS4
created by Larry G. Schneider in InDesign - View the full discussion