Mobile site logs warnings for every request

The mobile sites log the following warning for every request:

02.12.2011 12:44:31 WARN [org.hippoecm.hst.core.container.HstComponentInvokerImpl.invokeRender():212] Component exception caught on window langnavigation with component com.onehippo.gogreen.components.common.LanguageComponent: org.apache.jasper.JasperException: javax.el.PropertyNotFoundException: Property 'isAvailable' not found on type com.onehippo.gogreen.components.common.LanguageComponent$TranslationState at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
02.12.2011 12:44:31 WARN [org.hippoecm.hst.core.container.DefaultPageErrorHandler.logWarningsForEachComponentExceptions():49] Component exception found on com.onehippo.gogreen.components.common.LanguageComponent : org.apache.jasper.JasperException: javax.el.PropertyNotFoundException: Property 'isAvailable' not found on type com.onehippo.gogreen.components.common.LanguageComponent$TranslationState

Steps to reproduce:
1. open the mobile site (e.g. http://www.demo.test.onehippo.com/mobile)
2. observe the site log