SQL error when remove selected during adding files process.

If I add a full drive as source, Teracopy will add the NTFS folders $RECYCLE.BIN (and other hidden files (like dropbox.driver), if I try to remove them ( I tried this while TeraCopy is adding files) I get the following error:

The files and folders I remove is definitively removed from the list as far as I can see, but I am unsure if this is the case in the actual file list in the internal SQL store.

Could you shed some light on this issue? What is going on behind the scenes here?
Also, can you let me know what steps I can take to ensure that these files are copied over/some hidden issues are being caused in the background?