The errors in your log file seem pretty harmless. (The 'Fatal' error is some Eclipse/STS component trying to parse an empty .xml file somewhere, and it is being very vocal about this. The error is there all the time and not really an indication of a problem).
Unfortunately this leaves us with little info to diagnose a problem. The logs seems to say everything is ok. But what behavior you are describing seems to suggest that Gradle plugins are just not installed/active.
At this point I don't really have a good idea on what to do to diagnose it further. I'd recommend just trying to re-install the gradle plugins again, or is there a reason why you can't?
Low Bandwidth & firewall rules does not allow me to do so on site. I will have to try again from my home where I got it working in the first place.
Perhaps the solution for you is to install the Gradle plugins from a zipped up copy of the update site.
Here's one that you can try to use:
To install it go to "Help >> Install New Software". Then click the 'Add' button to add an update site. And add this zip as an update site. You shoyld then be able to install from the zip just like from an update site on the internet.
Note that this zip is actually a 3.0.0 snapshot build but it should be compatible with 2.9.1 STS (the gradle tooling doesn't have strong ties to any STS specific APIs, just Eclipse 3.7.2 APIs).
I would give you a pointer to a 2.9.1 version of the zip but I'm not sure where to find it ATM. When I find out I'll update this thread with the info.
Amazingly, that did not work either (at my workplace). I'll also try this zip from home to ensure I'm not going insane. I can't think for a moment how I can be having such problems with a copy of an eclipse that works fine on my home system, yet refuses to work on this system (and have no tangible error log with which I can infer issues from). I'll get back to you.
Thanks for your attention.
> ... did not work either
Did you get errors when you tried to install it?
Nothing that was logged, and there were no pop-up errors at all.