QGIS2Leaf Plugin installation error “cannot import name AlgorithmDecorator”

I have been using the qgis2leaf plugin and succeeded in creating interactive maps, adding legend, photos, etc. But suddenly I noticed that the OSM base layer has disappeared and the polygons are not getting published the way they are styled, so i tried reinstalling the plugin. And this is the message I am getting :-

I am unable to install the plugin. I am using QGIS 2.6.1 Brighton.

This seems to be a rather elusive issue. This thread suggests that restarting a few times might fix it.