When I open the Settings dialog and click the "Help" button, I get a message titled TortoiseProc with the following text:
Failed to launch help.
[OK]
I have not checked all the dialogs but the ones I've opened (Commit, Import, Export, Revert, Repository Browser, Resolve, Show Log) all open the online help.
I'm using TortoiseSVN 1.14.7, Build 29687 - 64 Bit.