See this document: Aperture 3.4 and later: Some third-party plug-ins are no longer compatible
Check with the manufacturer's of your plug-ins, if the plug-ins are compatible with Aperture 3.4.
To uninstall, remove them from the folder
They are either in the subfolder "Edit" or "Export", or both.
They should not interfere with Exporting, unless they are used as export plug-ins or the installer changed more in the system than putting the plug-in into the folder.