Hi Edwin,

All of a sudden, I'm having difficulty installing components to my master site.

Is it possible that I adjusted some settings during the last component install (to account for the component using some 'installer' code that didn't flow through to the slaves) and that this is affecting my ability now?

I've tried installing different components to the master, and keep getting the "not available on the master site" message.

Can you point me in the right direction?

If you have the message "not available on the master site" this is because you are trying to install the extension from a slave site.
If the domain is present in the list of slave site then this is a slave site.

So when you are saying that you install it from the master, I think this is false.
You are trying to install the extension from a slave.
Perhaps you have added the "master" domain in the list of slave and therefore converted it into a slave.

A master website is a website where the domain is not present in the list.
So you can create any subdomain of your master domain to recover a master URL that would be modified.