Many InfoPath developers have faced this issue several times when they make a bunch of views, tons of coding effort and a small modification in the form results into “InfoPath cannot open the selected form”.
There is not much information provided to help resolve this issue within the Event Log or any other location.
During my development experience I noticed that form templates that are signed and often have created this issue. Try the resolution below to workaround this issue and let me know if this works for you:
From the Menu > Tools > Form Options > Security and Trust > uncheck “Automatically determine security level” and select Full Trust > OK.
It would work for certain cases where this could be the problem. But not assured!
You can revert back the Security and Trust options as needed. Worth a try!