Apologies for the trouble!
I checked the file name, it definitely should be
cmap.zip. Likely the reason you are receiving the error from WordPress which is preventing the installation because it would actually overwrite the core Connections plugin which in turn would cause you a minor headache to fix. I suggest downloading the file again. It can be downloaded from your purchase history under the Downloads tab.
Make sure before updating that you first delete the cMap from the Plugins admin page, your data is safe when deleting cMap.
You can then install cMap again.
Hope that helps!