Yes, The missing step is...
Re-install the original standalone client from the wiki.
[removed]
scroll down to :
Download the TSO Client – 32bit: Download From Google Disk (20.10.2021)
Download the TSO Client – 64bit: Download From Google Disk (20.10.2021)
and install the client for your OS.
THEN, replace the .swf with the new one.