I went here but cannot see any means of reporting an issue: https://jira.codehaus.org/browse/SONARIDE
The issue is that SonarQube plugin in Eclipse stops working when project is configured as "Groovy Project" and DSL jar is added to classpath. The Sonar run crashes with message saying that it cannot find the Groovy DSL jar in "{build folder}\C:\Users....", which makes no sense - why the hell is it treating an absolute path as relative.
You can't create issue in JIRA by yourself. We prefer issues to be first discussed on our user mailing list (or on SO) in order to avoid too many "won't fix/not a bug".
In your case it seems to be a valid report so I have created https://jira.codehaus.org/browse/SONARIDE-430. In next Sprint of SonarQube Eclipse we plan to highly improve multi language support and Groovy is a good candidate.
If you could provide a simple Groovy project (including Eclipse metadata .project, .settings, ...) it would be very helpful.