Hmm the error generally means that the animation type is either blank or invalid. Try resaving the popup after changing the animation type.
The alternative is there is a JS conflict somewhere possibly with another JS based plugin like sliders etc.
A link would be helpful.
Ended up solving it… had to remake all of the popups.
The issue started because I was transferring from a testing environment. I moved the popups with default wordpress importer/exporter. First I moved some, and then later I moved the rest after I was done testing. All of the plugins that I had moved with the first batch (and wordpress did the ‘did not import X because it already existed’ thing) broke when the second batch was added – resaving didn’t fix it or anything. I just had to recreate them all together.
Ahh, strange. Thanks for the report back.
If you haven’t already please take a moment to rate and review the plugin and or support.