This is a super ZenPack but it may be more than you need. I have 1.1.0 of the Construction Kit and 1.0.0 of the HttpComponent ZenPack working on Core 4.2.3.
However, if all you want to do is test a URL then you may find it easier to get started with ZenPacks.zenoss.HttpMonitor. This is one of standard bundle of Core ZenPacks that come from Zenoss and was probably installed when you installed your Zenoss Core. You can find basic instructions for it in the Zenoss Extended Monitoring guide.
The ZenPack you are working with is a community contribution and can do lots more for you - worth coming back to when you have spent a little more time with Zenoss.
Cheers,
Jane
