You may want to use strict; inside the code for VRTSAgent (after package VRTSAgent;). It looks like you're using several undeclared variables, and this may help you catch some errors.

Another thing I notice right off the bat is these two lines:

        $agents[++$j]= new VRTSAgent;
        $agents[$j]->new();
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The first statement calls new(), so there's no need to call it again. In fact, when you do call it the second time, you're passing a VRTSAgent object as the first parameter rather than the name of a class, as your new() expects.