Subtitle pop up

[BSPeter]

No such problem here using BS.Player Pro version 2.43 Build 1008 (21-07-09).
I repeat my suggestions (plus some additional):
(rightclick >) Options > Preferences > Subtitles > [Online subtitles]
(1) Deselect (i.e. uncheck if checked) "[ ] Enable online subtitles"
(2) also deselect "[ ] Download only if local subtitles are not available"
(3) as well as "[ ] http://www.opensubtitles.org/xml-rpc"
(4) Maybe close and restart BS.Player.
(Just another question in between: are other changes in preferences remembered the next time you use BS.Player; if not, there may be another issue fooling us around!)

(5) If after that you're nevertheless asked by BS.Player:

reply with "Don't" selected (as shown)

Only if the above doesn't help:
(rightclick >) Options > Preferences > Subtitles > [Subtitle properties]
(6) Select "[v] Subtitles disabled"

You actually didn't reply if you tried as indicated (1-6) by me, whereas your info concerning the version you're using (on which version has the problem and/or which version hasn't) is a bit confusing. I know there has been a version in the past which had this bug (can't remember which though; maybe it is indicated in the file changes.txt; I'll have a look).