We only ran your harnesses against our test cases, because there was an error in the test language specification, and none of your test cases would have passed our test case administrator through no fault of yours.
The test cases are available as a ZIP and as a tarball.
Several common errors:
timeout: The player took longer than 3 seconds.
expected root element - received #<eof>: The player closed its stdout before completing the transaction. This probably indicates that the player crashed, possibly with an uncaught exception.
expected root element - received #<struct:pcdata>: The player wrote something that isn't an XML element to stdout.
Broken pipe; errno=32: The player closed its stdin before the test fest administrator had finished writing to it. Again, this probably indicates that the player crashed, possibly with an uncaught exception.