What is this error... ?

$ echo "panic: Devel::DProf inconsistent subroutine return at /usr/loc
+al/share/perl/5.10.0/JSON.pm line 54." | splain
panic: Devel::DProf inconsistent subroutine return at
    /usr/local/share/perl/5.10.0/JSON.pm line 54 (#1)
    (P) Devel::DProf called a subroutine that exited using goto(LABEL)
+,
    last(LABEL) or next(LABEL). Leaving that way a subroutine called f
+rom
    an XSUB will lead very probably to a crash of the interpreter. Thi
+s is
    a bug that will hopefully one day get fixed.
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So maybe check if that is what's happening at .../JSON.pm line 54