I seem to be having the same problem. However, this plugin works perfectly on localhost but not on a remote server. Firstly, I had checked that the database does not have the 4 tables created. I then went and install the plugin. Now, osclass registers the plugin as installed but the 4 tables are not created at all in the database. This problem does not manifest itself on localhost, strangely. I've put OSC_DEBUG and OSC_DEBUG_LOG to true but I don't see any error coming out.
I am not sure whether this is affected by the recent update. I've tried debugging and it seems to me that osclass install hook is not calling the plugin's install function. I will try to do the same with the previous stable release and update on this thread.