I originally created in CS6 version of InDesign in the CS5.5 version. It is giving me a plug-in error. I tried searching for updates using the HELP feature, but it stated my connection was not working and to try later. Can anyone help me with this problem? Thanks in advance!
InDesign files (Filename.indd) created in any version of InDesign cannot be opened in an earlier version. What you can do is to export to a different format, which an earlier version can open, but with some caveats. If you still have the newer version, open the file and go to File>Export and choose IDML. 5.5 should be able to open an IDML from 6. The caveat is that if there is a feature in the new version that isn't present in the old, the file will be different to a degree. The example I used to use years ago with Quark was when they added the type-on-a-path feature, and if you backsaved, any type on a path would still be in the file, but in a rectangular text box because the older version has no idea what type-on-a-path is.