Quickly posting for reference (I have to go bed **now**! LOL)
Database error, given array of integer values is empty. (not_id_attach)
Function: removeAttachments
File: /[...]/sources/subs/ManageAttachments.subs.php
Line: 187
The 'attach_del' is triggered (probably because of some concurrence between D&D upload and the normal form), but if there are no attachments to keep the query fails.
Fixed with a trick:
https://github.com/emanuele45/Dialogo/commit/9cac20b5d824ae6ef96704e7252bfa7702f47963
The proper fix is a proper handling of the removal of the attachments. 1.1
ETA: fix applied here as well.