In your project you have the Datalinq Server list, where you add your Datalinq Server(s). Is yours set to 'localhost/127.0.0.1' or an IP address?
When your project is loaded onto the Preview Engine, which drives the previews in the plugins, the Preview Engine is going to try and connect to the Datalinq Server address that is stored in the project. If the Preview Engine can't find a Datalinq Server (with the correct Data sources) at the location that the project has saved then it won't be able to generate a preview frame with Datalinq content.
Try saving and publishing your project with the IP address of the Datalinq Server you are using in it.
#XPression