Hi Alexey
Whether parent or child process, and whether using a default name (solution plus date/time) or a name template, ensure that what you specify doesn't already exist in the documents library with the same name. If you are launching multiple child processes at the same time, ensure they have unique names.
I have only run into that with name templates myself, where I said to start renumbering when I published but I forgot to get rid of the old documents.
If that's not the case, I suggest you open a support ticket so that they can take a look with you.
Best Regards,
Sigrid
------------------------------
Sigrid Kok
Precisely Software Inc.
------------------------------