When opening a .DML file into the Query Builder in Toad, the following error appears:
Access violation at address 00E82193 in module 'TOAD.exe'. Read of address 04B6235C
List index out of bounds (0).
This can be an issue when trying to open some older .DML files into a more recent version of Toad.
Re-create the Queries in the current version of Toad, and save a new version of the DML file.
Waiting for fix in a future release of Toad for Oracle.