Here is your answer.. sounds easy enough I think. If you need further help with this, please let me know.
Turns out there's a really fast way for the user to fix this. SmokinHusker has set her subscription preferences in an unusual way which leads to this problem:
1. She has set her default subscription frequency to "don't subscribe" <-- this prevents her from being auto-subscribed to threads when she posts. She should keep this setting.
2. She has also checked the box for "Don't ask me" <-- this prevents the dialog box asking what frequency you'd like, and since her default is "don't subscribe," there's nothing we can do to subscribe her without disrespecting her preferences.
Both of these, together, make it impossible to subscribe to things. She's basically said "don't subscribe, and don't ask me."
I would suggest that she uncheck the "Don't Ask Me" box. This will allow her to manually press the "subscribe" button, but it will not result in her getting automatically subscribed to anything (which she obviously does not like).
This checkbox is located on the "Edit Subscriptions" tab.
It looks like this:
For our part, I think we could do more to organize these preferences a little better so this doesn't happen in the first place. I'm going to work on that.
But the quick fix for SmokinHusker is to simply uncheck the "Don't Ask Me" box.