Your forms would have been saved with a newer version of Delphi. Unfortunately you will need to open each form in the IDE and save it again to clear the newer properties. There is a tool that can help you called DFMCheck (http://andy.jgknet.de/blog/ide-tools/dfmcheck/). This is an add on that will go through all of your forms and tell you about any problems with the forms that will only show up at runtime.
The reason why you are seeing the problem is this. Delphi saves the forms with all of the properties. It uses streaming to load the forms at runtime. When it tries to load a form with properties that don't exist then you will get an error like this as the streaming system is trying to set a property on a component when the property doesn't exist.