hellokitty11583 That particular error typically comes from an old (pre-64-bit) copy of Version.tag, inside Documents > Electronic Arts > The Sims 3. Delete this file and it should go away. The odd thing is that you'd have this file at all, in that you'd have had a newer one while playing.
Do you use iCloud Drive, and is it syncing the contents of Documents? One reason I suggested playing offline is that iCloud syncing during a play session can temporarily lock up the user folder and cause crashes, if the timing is just wrong; but iCloud can't sync without an internet connection. This could also explain where the old copy of Version.tag came from—it was always in cloud storage and somehow got downloaded to your computer again recently.
An old copy of Version.tag may not be the only cause of this error; it's just the only one I've had confirmed over the past few years. So if deleting it doesn't help, try removing or renaming the entire Sims 3 folder in Documents > Electronic Arts to see whether the error still shows up.