7.7.4 compilation problem with SBT

I had a working project and I upgraded to 7.7.4 to accomodate the free chart wrapper and now I cannot compile. Errors are below. Any ideas? 

[info] Compiling 13 Scala sources and 4 Java sources to /amcs/develop/sss.asado/sss.asado-analysis/target/scala-2.11/classes...
[error] jar:file:/home/alan/.ivy2/cache/com.vaadin/vaadin-server/jars/vaadin-server-7.7.4.jar!/com/vaadin/ui/JavaScript.java:40:  com.vaadin.ui.JavaScript
[error] public 
[error] jar:file:/home/alan/.ivy2/cache/com.vaadin/vaadin-server/jars/vaadin-server-7.7.4.jar!/com/vaadin/server/BootstrapHandler.java:42: cannot access com.vaadin.annotations.JavaScript
[error]   bad source file: /home/alan/.ivy2/cache/com.vaadin/vaadin-server/jars/vaadin-server-7.7.4.jar(com/vaadin/annotations/JavaScript.java)
[error]     file does not contain class com.vaadin.annotations.JavaScript
[error]     Please remove or make sure it appears in the correct subdirectory of the sourcepath.

So I stripped out all the .java files from vaadin-server-7.7.4.jar in the local ivy cache.... and frighteningly, this allowed the project to compile and run. 

Can anyone offer an explanation for what's going on here?