I have not used Acrobat Writer myself so I can't vouch for that the problem isn't due to incorrect usage, but there is another angle on this.

Which version of w32 and Word are you running on?

I've had problems with code running fine on w98 and Office 97, but fails on XP and Office 2000.

Haven't really determined the exact culprit but the solution was to access the Wordconstants in this manner instead.

use Win32::OLE;
use Win32::OLE::Const; #Note const not loaded here
.
.
.
my $wdConst = Win32::OLE::Const->Load("Microsoft Word"); #const loaded
+ explicitely
.
.
$doc->PrintOut({
                     PrintToFile => 1,
                OutputFileName => "$dir/test.pdf",
                Background => 0,
                Append     => 0,
                Range      => $wdConst->{wdPrintAllDocument},
                Item       => $wdConst->{wdPrintDocumentContent},
                Copies     => 1,
                PageType   => $wdConst->{wdPrintAllPages},
               });
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Note this is untested, coming directly from my old and crufty memory, so check the docs for exact syntax.