Using diagnostics reveals this info: 
Insecure dependency in rename while running with -T switch at 
    (F) You tried to do something that the tainting mechanism didn't l
+ike.
    The tainting mechanism is turned on when you're running setuid or
    setgid, or when you specify -T to turn it on explicitly.  The
    tainting mechanism labels all data that's derived directly or indi
+rectly
    from the user, who is considered to be unworthy of your trust.  If
+ any
    such data is used in a "dangerous" operation, you get this error. 
+ See
    perlsec for more information.
    
Uncaught exception from user code:
        Insecure dependency in rename while running with -T switch at

[download]
Since you are not explicitly using -T, look into setuid or setgid.

By the way, changing readdir to glob will not solve the double-digit filename issue.

In reply to Re^3: Problem with renaming files in directory by toolic
in thread Problem with renaming files in directory by ice_ice_ice

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