Bilingual TB refuses to do its job (update / find / add terms)

I think I'ave already put a similar questions months ago. A termbase which is sort of restive was exported in MultiTerm to xml and then reimportet into MultiTerm while using the same template as that of the export sdltb. Now it is neither possible to enter a term in Studio 2015, nor is it possible do so in MultiTerm 2015 nor does Studio detect any terms present in it. Under "project settings" I can see it IS the active and only TB. The error message in MultiTerm is:

"MultiTerm was unable to update the entry. No new data has been saved.
Type    System.Runtime.InteropServices.COMException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToke
ErrorCode   -2147220910
 HelpLink
Source      Entry
HResult      -2147220910
Stacktrace
     at Sdl.MultiTerm.TMO.Interop. Entry Class.Save()
     at Sdl.MultiTerm.Client.UI.Viewer.ScriptingHost.SaveEntry(String content)"

Any idea what this "Chinese" means? By the way, the TB did work properly yesterday, only changes to it imply adding a few terms via Studion 2015.