For the TCL module in sBNC to be compiled, it needs the libraries from TCL to be installed on the server. Here is a brief overview of what the package is called on the different unix distributions. Inspired by http://irc-guide.de/wiki/Main/TCLInstallation.

$> apt-get update
$> apt-get install tcl8.4 tcl8.4-dev

$> emerge --sync
$> emerge tcl

• First try installing the packages using YaST. Their names should be “tcl” and “tcl-devel”.
• If they aren't in your repository, go to ftp://ftp.suse.com/pub/projects/tcl/8.4.12.
• Choose the appropiate subfolder according to your version of SuSE.
• Download the two files starting with “tcl-”.
• Install using (replace filenames with the ones you downloaded):

  $> rpm -i tcl-8.4.12-5.1.i586.rpm 
  $> rpm -i tcl-devel-8.4.12-5.1.i586.rpm
  

See http://wiki.tcl.tk/2422.

If you can't use any of the solutions above, or just have a general desire to do everything 'by hand'. You can get the sourcecode of TCL from http://www.tcl.tk/.