I had been running an earlier version of STS and had a tc Server instance.
I deleted my old STS install. I installed 2.9.2.RELEASE and started it, opening my existing workspace.
I deleted my tc Server instance. I tried to create a new tc Server instance
via Servers -> New but there are no templates, so the wizard cannot complete. There was no indication of a configuration error.
If I try this in a new (clean) workspace, I can delete and add
tc Server instance.
The server definition in my Window -> Preferences -> Server -> Runtime Environments was old - it
had the old tcServer from a previous (2.9.1.FINAL) install of STS (tc Server 2.6.4 instead of 2.7.0).
I edited my runtime environment to point to my current STS install,
and now it now works.
Perhaps the STS server plugin should ensure that Server Runtime Environments contains the bundled tc Server - otherwise upgrades such as mine (using an existing workspace) may fail. It's probably rare - requires manually deleting the server from the Servers view - but possible.
(at a minimum, since this bug report exists, folks can find the workaround)