E-newsletter plugin widget not working in later versions

Hi,
I'm having a big problem with the e-newsletter plugin widget. I had it working well several months ago. Then I upgraded and it stopped working. I had thought it was a change a developer made but after my trouble shooting the problem, I don't believe it is.
The problem I am seeing in the later versions is that the subscribe button in the widget is dead. It doesn't do anything at all.
The trouble shooting I have done to date has been:
1. Completely uninstall the plugin, drop all associated tables and then install a fresh version of the plugin and reconfigure it. Result- No change.
2. Checked for plugin conflicts by turning off all plugins except for e-newsletter. Result- No change.
3. Tried an older version of the plugin that I have on another site. I tested version 1.2. It works fine but I still have the problem I had when I was using the older version in that the look and display text on that widget is not at all what I want. The newer version is fine.

I would like to be able to continue using this plugin as I need the integration with membership and changing my whole mailing system will be a pain I can do without. I'm really not sure how to proceed from here though. I need some way to display a signup in my sidebar.
Any ideas?

With thanks,

Julie