Hello.
Test case: start slime with ECL and compute in the REPL bufer: (/ 1 0) Instead of showing SLDB buffer emacs reports: error in process filter: Wrong number of arguments: nil, 0
This happens because stack frames list in the :debug message received from swank is empty.
Corresponding changes were committed at August 12, 2008. I do not know what the proper fix will be, but at least reverting EVAL-FOR-EMACS as in the diff attached makes the SLDB buffer with stack trace appearing.
Best regards, -Anton