I installed CartoDB on a digital ocean instance of Ubuntu 12.04. I am able to log in and import data. Table view is fine, but map view does not show tiles with the message "There is a problem with your connection". I assume this means problems with the Windshaft tile server. 

Windshaft installs ok: 

```
git clone git://github.com/CartoDB/Windshaft-cartodb.git
cd Windshaft-cartodb
git checkout master
npm install

```

but `make check` fails; nine failing tests with two primary errors: 

```
AssertionError: "2.1.0" == "2.1.1"

```

and

```
Uncaught Error: listen EADDRINUSE
    at errnoException (net.js:769:11)
    at HTTPServer.Server._listen2 (net.js:909:14)
    at listen (net.js:936:10)
    at Server.listen (net.js:993:9)
    at dns.js:71:18
    at process.startup.processNextTick.process._tickCallback (node.js:244:9)

```

The only thing I changed in config/environment/test.js was to set Mapnik version to 2.1.1. 

I've posted the full output of `make check` here:
<http://pastebin.com/CWSfijR8>

Any ideas on what I'm not configuring or installing correctly? Or how else to troubleshoot these errors? 

(follow up and update from question originally posted in [CartoDB google forum](https://groups.google.com/forum/#!topic/cartodb/ssy6T1wt22k))