FlashBuilder "Hello world" project compile failing, 'closure-lib' doesn't point to valid directory

I've tried installing the latest royale-asjs from both the npm package and from the binary distribution ZIP download (0.9.7). I've followed the instructions to set up with Flash Builder 4.7, but after converting the empty "Hello world" Flex project to Royale, the build fails:

1309: java.lang.RuntimeException: Parameter 'closure-lib' doesn't point to a valid directory. org.apache.royale.compiler.internal.codegen.mxml.oryale.MXML.RoyalePublisher.publish(MXMLRoyalePublisher.java:359)orge.apache.royale.compiler.clients.MXMLJSCRoyale.com

Windows 10
Flash Builder 4.7 Professional
FB JRE - Oracle 1.8.0_251-b08

Reproduce the empty Hello world Flex-to-Royale build in Flash Builder 4.7 on Windows 10 using the 0.9.7 package or ZIP. Start at MXMLRoyalePublisher.java:359 and inspect how the closure-lib parameter is configured; done means the project compiles without the invalid-directory exception.

Written by the indexing model from the issue text.