Sitemap unreachable: "Waiting on localhost"


after setting up everything I’m trying to display the sitemap I’ve created. To do that I start openHAB by launching start.bat. That seems to work fine, no errors are shown. Also some UDP messages I expect to receive are shown.

When accessing the sitemap in Firefox nothing happens but the message “waiting on localhost” is displayed.
Then I terminate openHAB by typing “exit” which results in the message “Stopped REST API” but the windows doesn’t close.

I repeat this several times before I finally can access the sitemap in the browser. After a while the sitemap stops working with the already known message “waiting on localhost”.

To my knowledge the sitemap and items etc. are OK. The designer doesn’t indicate any problems. Also this confiuration previously has successfully been used on a different computer. And after all, when the sitemap finally works for a few minutes nothing indicates a problem.

I’ve tryied both openHAB 1.6.2 and 1.7.1 with Java 1.6.2 and Java 1.8.0 on Windows 7, 64 bit, Firefox and Windows Explorer.

I would be nice if someone could give me a hint how to fix that problem.

I’d like to add two observations:
While the browser is trying to load the sitemap with the message “waiting on localhost” I terminated openHAB (exit + closing window manually). Then the browser displayed a site “Error: Connection failed”. That indicates it somehow communicated with openHAB before the program was terminated.
Also while waiting for the sitemap to be displayed a ping to localhost from a new console windows is successful.

Does this information help anyone to point to the problem?