IDE doesn't show "build-variants" caused by: "Gradle 'linkedGradleProject' project refresh failed: A path must be specified!"

After installation of AS 0.2.10 the studio didn't show any "build variants" and I got the following message:
"Gradle 'linkedGradleProject' project refresh failed: A path must be specified!"
In my gradle settings (File -> Settings -> Gradle) I wanted to use "default gradle wrapper (recommended)".
But this option was disabled and a comment was "(not configured for the current project)".
Also I recognized that the linked gradle project was the wrong one (the root folder of my android studio projects -> in earlier times there was a bug in AS where changes in the gradle.build file caused a reorganization of the prject: the IDE generated an "*.iml" file to the parent folder of the project).

The solution was simple:

•  close the project
• import project
• choose the "settings.gradle" file of you project
• a dialog occurs: "Import Project from gradle"
• now you have the option to "Use default wrapper (recommended)"
• if you still get the message of the "linkedGradleProject" just restart the IDE than it shouldn't appear again.
  But the important thing is that the IDE shows your "build-variants"!