diff --git a/doc/building-the-code.txt b/doc/building-the-code.txt
index 54fce8b..14a739c 100644
--- a/doc/building-the-code.txt
+++ b/doc/building-the-code.txt
@@ -25,8 +25,8 @@
 `apt-get install subversion git g++-multilib gcc-multilib ruby patch \
     make openjdk-6-jdk default-jdk libevent-dev:i386 libevent-2.0-5:i386`)
 
-Also run `apt-get install powerpc-wrs-vxworks` if you want to be able to build
-  the cRIO code too.
+Also run `apt-get install powerpc-wrs-vxworks tcl` if you want to be able to
+  build the cRIO code too.
   NOTE: This is in *addition* to the above commands.
   You will have to accept the
     "WARNING: The following packages cannot be authenticated!" warning for the