BEGIN {
  @INC = ();
  ...
[download]

...might not be a good idea to clear the @INC array first, because in this case the standard modules will no longer be found (unless you copy all of them into one of the directories specified).

$ perl -e 'BEGIN{ @INC=(); unshift @INC, ".", "/home/user/perl/lib"} u
+se File::Find'
Can't locate File/Find.pm in @INC (@INC contains: . /home/user/perl/li
+b) at -e line 1.
BEGIN failed--compilation aborted at -e line 1.
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In the typical case, you just want to BEGIN{ unshift @INC, ... }, or use lib ... to prepend additional search paths to the system paths that @INC already consists of...