I'm not sure what you're asking. Do you want to know if err 4261 still exists? It does - I was getting it several months ago in 4.1. It pertained to too many spool files in the BR folder. Once I moved my spool files to another folder (and redirected them there via BRCONFIG.SYS Spoolpath command, the problem went away:
What I meant to as is: Is error 4261 still an Operating System Error 61 in current versions of BR!?
I am fully aware that in BR! versions 4.15999 and below it is an Operating System Error 61, but in versions 4.16 and above I do not believe it is. And if that is correct we should correct the summary on most of the old OS based error numbers. That is if the information in the link i provided (above) is accurate.