I could not reproduce your problem on perl v5.8.3 and Time::Local ver 1.07. I get no warnings, and a different answer: 
> perl -MTime::Local -we "print timelocal(0,0,0,15,6,2005),$/"

---output--
1121410800

[download]
Your problem may be related to this note in Time::Local, Changes for 1.11

"1.11 2005-02-09 - Try to make detection of supported epoch range a little smarter.
The detection was allowing negative epochs on Win32 but apparently this doesn't work, and trying to pass a pre-epoch date in just causes a lot of warnings. ".

     "Income tax returns are the most imaginative fiction being written today." -- Herman Wouk

In reply to Re: Time::Local and warnings by NetWallah
in thread Time::Local and warnings by Tanktalus

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