Take a look at .../share/vim/vim???/doc/debugger.txt (or from within vim :help debugger) -- quote from this text:

Currently the only fully integrated debugger/IPE/IDE is Sun's Visual WorkShop Integrated Programming Environment.

This is from the latest release, checkout Vims home page for more info, but I guess if it is availible it aint in vim by default. I found nothing on perl.com either.
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Zigster