I'm not sure whether it's related, but I also got lots of ";Can't define name; already free:" errors in code that had been working before.  Reordering definitions worked around this problem.  It alwayas happened when a macro referred to a binding that hadn't yet been defined in the same file.

Compiling a library that includes the syntax definition below results in a "has free references not provided by imports:" that includes many extraneous identifiers.

(define-syntax define-test-group
  (syntax-rules ()
    ((_ test-group-name
        test-procedure
        row ...)
     (let ((procedure test-procedure))
       (install-test-group! 'test-group-name
                            (list
                             (make-unit-test
                              (append 'test-group-name row)
                              (lambda () (apply procedure row)))
                             ...))))))

Here's the message:

Library (unit-test) has free references not provided by imports: (row test-group-name test-procedure procedure expression test-name)

Note that the macro's arguments and its local bindings are included, which is probably not the intent.