Couple of issues. 0. depends on dev-java/joda-time. The stable version, 0.95, does not compile with xstream-1.2. Went unstable (1.3) and compile succeeded. 1. src_compile() refers to javadocs, should be javadoc.
Fixed in CVS (joda-time is set to >=1.2 because it compiled with 1.2 as well, not with any version below though). Thanks for reporting!