bug in amaya GTK 6.4/: Not saving annotations

I cannot save local annotations with amaya GTK 6.4: If I try it, the 
file .amaya annotation.index is modified; lines like

(null) file:///home/mfvm/.amaya/annotations/indexB8CG4w

are added and the annotations content is saved in an annot######.htm 
file. But the file indexB8CG4w is not created.