luxman, bradleyclarke, did you try downloading (manually) and uploading (via FTP) the plugin? The version currently in the plugin repository identifies as the same version you probably already have, but actually does contain different code that fixes the error.
Bradleyclarke, I did have problems sometimes trying to access the dashboard, but usually if I refreshed the page I could get in.
I also developed issues with another plugin at exactly the same time, again on multiple sites, so obviously HostGator is making some sort of configuration change to their servers. Regarding the other plugin, they told me they needed to whitelist the URL for a mod_security rule, but refused to tell me which one. (I don’t know, but suspect it may have something to do with fopen) If you go to them and ask them to find the error in their logs and find the appropriate mod_security rule to whitelist, that may take care of the same issue, or related issues that happen at the same time.