My post earlier in this thread has a short v1 and v2 script that reproduce the issue with v2 Acc_Children() throwing error.
The scripts can be used with Acc v2 version by eugenesv's 2022-02-22 (latest) from viewtopic.php?p=433516#p433516
and Acc v1 from https://github.com/Ixiko/AHK-libs-and-classes-collection/blob/master/libs/a-f/ACC.ahk
I could copy and paste all this to "Autohotkey v2 Help" section. But as this thread already covers discussion/troubleshooting for the two v2 Acc work in progress library attempts isn't it better to continue that discussion here?
edit:
I tried to track down different Acc v1 versions, and ended up with this list
2010-02-25 https://github.com/Drugoy/Autohotkey-scripts-.ahk/blob/master/Libraries/Acc.ahk
2012-02-19 https://github.com/Ixiko/AHK-libs-and-classes-collection/blob/master/libs/a-f/ACC.ahk
2012-10-25 https://github.com/evilC/Spreadsheet-Barcode-Scanner/blob/master/scanner.ahk#L525 (embedded in larger script)
There's also
2019-05-10 https://github.com/sancarn/ACC.AHK (forum thread). But note that author sancarn says "incompatible with old Acc.ahk scripts"
This @just me 2017 code may also be relevent to v2 Acc efforts
viewtopic.php?t=40532#p189883