Unless you have a specific reason for attempting to compile the Tk module yourself, you should probably use the pre-compiled modules that ActiveState provides. Assuming you have a working internet connection, typing:

ppm install Tk
[download]

..at a command prompt should do the Right Thing. For more information about the joys of PPM, read ActivePerl-faq2

perl -pe '"I lo*`+$^X$\"$]!$/"=~m%(.*)%s;$_=$1;y^+*`^ ve^#$&V"+@( NO CARRIER'