Consolidating backup versions

I have tried to Consolidating backup versions using; ‘Click Operations on the selected backup's box and select More → Consolidate versions’. The consolidation window appears, and states that it is calculating the time, and that’s all that happens. I left my computer running overnight and the same window was present with the same status, nothing seems to be happening. I have run out of space and need to consolidate / delete old backups in order for Acronis to continue to backup my data. Can someone PLEASE help me in getting this option to work?? I am running Acronis True Image Home 2011 on Windows 7 (64 bit) OS.

Thanks!!