DEVONThink Pro crash, after moving indexed folder

Dear community,

I had (or has) an indexed Finder folder, containing a lot of academic papers, classified by author. I indexed in DEVONThink Pro, and I had no problems until I moved that folder in the Finder. I proceeded to delete the DTP group, in order to re-index it, but I CANT delete the group as DTP crashes every time I try.

Have you any ideas of why does this happen? How can I solve it?

Thanks a lot.