JavaFX application could not launch due to system configuration. (Found unsigned entry in resource:)

I've got the following message when I tried to run simple signed JavaFX app with WebView.

"JavaFX application could not launch due to system configuration. See java.com/javafx for troubleshooting information."

Unfortunately, this message doesn't tell what the problem is and the referenced site has no troubleshooting information. The site actually recommends to install JavaFX Runtime either x32 or x64. I tried both - either is telling that I have newer version installed on my system.