I've just checked and find out that there is no vboxadd, vboxadd-service and vboxadd-X11 binaries in /etc/init.d. Can you describe me your way of creating extension? My was:
1. Prepare environment:
-number of packages installed: compiletc, usb-utils, make, gcc, linux-api-headers, util-linux-base, module-init-tools, libmpc, libmpc-dev, squashfs-tools.
-download TCL kernel sources, unpack it to external storage.(for example to sdb1/000/linux-3.0.3/)
-next actions was performed
mkdir -p /usr/local/lib/modules/3.0.3-tinycore/kernel
ln -s /mnt/sdb1/000/linux-3.0.3/ /lib/modules/3.0.3-tinycore/build
-create time-stamp mark.
2. Install VBoxLinuxAdditions.run with regular installer
3. Change line in /etc/init.d/vboxadd
daemon $binary > /dev/null
($binary > /dev/null) &
4 determine number of files was changed during install, base on time-stamp previously created.
5 create archive from these files
6 TCL extension was created base on archive we've got on previous stage.
But I did this on VB 4.1.2, but I don't think it has significant difference with 4.1.4. If you'll insist I'll repeat my installation on updated version.