I ran in the same error and here is the "empirical" way I found to solve it.
I'm working on a Windows XP machine with Activeperl 5.10.0 Build 1003. My CAM-PDF module version is 1.13, the versions of its dependecies are Text-PDF module version 0.29 and Crypt-RC4 module version 2.02

As CaMelRyder reported, from this simple program:

use strict; use warnings; use CAM::PDF;
my $pdf = CAM::PDF->new("test.pdf"); # test.pdf is the existing pdf
my $string = $pdf->getPageText(1);
open (C, ">", "test.txt"); print C $string; # print extracted string
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.. I obtained this error:

Failed to open filter FlateDecode (Text::PDF::FlateDecode)
Unrecognized type in parseAny:
1 ���═��╩▓��▀O▒:♠�n��╩...
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the really strange thing was that adding ONE LINE at the beggining of the program:

@INC=('C:/Perl/lib','C:/Perl/site/lib','.'); # THIS LINE IS ADDED
use strict; use warnings; use CAM::PDF;
my $pdf = CAM::PDF->new("test.pdf"); # test.pdf is the existing pdf
my $string = $pdf->getPageText(1);
open (C, ">", "test.txt"); print C $string; # print extracted string
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everything worked fine and no error message was displayed.
What I've done is a very little change to the Perl special variable @INC which is: (from perldoc)
"The array @INC contains the list of places that the use construct look for its library files."

Usually the content of this array @INC is ('C:/Perl/site/lib','C:/Perl/lib','.') I verified that by typing from the command line of my computer: perl -de0 in this way I opened the perl debugger and I typed: x @INC
On resume, I obtained that:

usually _______________ => @INC is ____ ('C:/Perl/site/lib','C:/Perl/lib','.')
to make CAM-PDF working => @INC must be ('C:/Perl/lib','C:/Perl/site/lib','.') => I INVERTED THE FIRST TWO ELEMENTS OF @INC

I DON'T KNOW THE REASON OF ALL THAT, AND I WAIT FOR EXPLANATIONS FROM SOME PERLMONK MORE EXPERT THAN ME.