Hi Julia,
I'd suggest you to take a look at the following issues:
– js errors. Debug the web page and see why you get the js error. These errors can compromise the functionality of the QWP
– you don't need to use a new/different strong key but you can do it if you want to
– debug your custom code to be sure that no exceptions happen there
– after you set your custom actions within QWP move the custom actions assemblies to the GAC and do an iisreset
– in your custom action (not the code you set up but the QWP chain of custom actions) make a save custom action first then reset the session
Let us know how it goes.
Thanks,