ODataExplorer fails on s11hanaxs

Hi,

when I try to start the ODataExplorer from the HANA WebIDE, the application loads but diplays no data. In the Web Debugger I see that https://s11hanaxs.hanatrial.ondemand.com/sap/hana/xs/dt/base/workspace?_=1455179822957 fails with statu 555 and the body

{"HttpCode":555,"Severity":"Error","Message":"Error in Request Processing: oSapBackPack is undefined"}

How can I prevent this?

Thanks in advance,

Wolfgang