Trouble installing PerlTk (5.1)

[fenzda]

I am having trouble installing the perl tool kit(Perl Tk).

I gtar'd the file and created the directory and all.

When I tried to run perl Makefile.PL it told me I couldn't find
the X11R5(or 6) link.

I even tried to download it from a CPAN mirror with same result.

(1) Why is this happening (2) Why isn't PerlTk included with
Knoppix(I have 5.1) (3) Isn't X11 already installed?

I have no clue how to fix this.

Here is what fails when I run

perl Makefile.Pl:

/UNIONFS/usr/bin/perl is installed in /usr/lib/perl/5.8 okay
PPM for perl5.008008
Test Compiling config/signedchar.c
Test Compiling config/Ksprintf.c
Test Compiling config/tod.c
Test Compiling -DTIMEOFDAY_TZ config/tod.c
TZ gettimeofday()
Using -L/usr/lib to find /usr/lib/libX11.so.6.2.0
Cannot find X include files via /usr/include
Cannot find X include files anywhere at ./myConfig line 332.
Compilation failed in require at Makefile.PL line 36.
BEGIN failed--compilation aborted at Makefile.PL line 38.