Thanks for your help - here's what I've done to date:

I used the latest version of Virtual Box (4.18) to create a virtual machine with 8Gb SATA HDD and 1GB of RAM.

I installed Ubuntu Desktop 11.04 with all the defaults

From the instructions at http://genode.org/documentation/developer-resources/getting_started as a base...

GNU make 3.81 - was already installed

I used apt-get install to install libSDL-dev

I initially had issues finding tclsh, as it wanted me to pick a version, but then I get it as part of apt-get install tcl

I used apt-get to install expect,qemu,genisoinstall

Added virtualbox guest addins to get cut-paste working for this url

http://downloads.sourceforge.net/project/genode/genode/12.05/genode-12.05.tar.bz2?r=http%3A%2F%2Fsourceforge.net%2Fprojects%2Fgenode%2Ffiles%2Fgenode-toolchain%2F&ts=1342966018&use_mirror=iweb

I then renamed the file, and used tar -xf to extract it...

Here's the output from the session after that...

====================================================================

mike@...123...:~/genode-12.05/build.lx$ make run/demo

/bin/bash: /usr/local/genode-gcc/bin/genode-x86-g++: No such file or directory

dirname: missing operand

Try `dirname --help' for more information.

using run script /home/mike/genode-12.05/base-linux/run/env

using run script /home/mike/genode-12.05/os/run/demo.run

building targets: core init drivers/timer server/nitpicker server/liquid_framebuffer app/launchpad app/scout test/nitpicker server/nitlog drivers/framebuffer drivers/pci drivers/input

spawn make core init drivers/timer server/nitpicker server/liquid_framebuffer app/launchpad app/scout test/nitpicker server/nitlog drivers/framebuffer drivers/pci drivers/input

make[1]: Entering directory `/home/mike/genode-12.05/build.lx'

/bin/bash: /usr/local/genode-gcc/bin/genode-x86-g++: No such file or directory

dirname: missing operand

Try `dirname --help' for more information.

checking library dependencies...

/bin/bash: /usr/local/genode-gcc/bin/genode-x86-g++: No such file or directory

dirname: missing operand

Try `dirname --help' for more information.

/bin/bash: /usr/local/genode-gcc/bin/genode-x86-g++: No such file or directory

dirname: missing operand

Try `dirname --help' for more information.

Skip target drivers/framebuffer/fiasco_ux because it requires fiasco

Skip target drivers/framebuffer/pl11x/pbxa9 because it requires pl11x platform_pbxa9

Skip target drivers/framebuffer/pl11x/vea9x4 because it requires pl11x platform_vea9x4

Skip target drivers/framebuffer/pl11x/vpb926 because it requires pl11x platform_vpb926

Skip target drivers/framebuffer/vesa because it requires vesa

Skip target drivers/input/fiasco_ux because it requires fiasco

Skip target drivers/input/ps2/pl050 because it requires pl050

Skip target drivers/input/ps2/x86 because it requires ps2

Skip target drivers/timer/codezero because it requires codezero

Skip target drivers/timer/fiasco because it requires fiasco

Skip target drivers/timer/foc because it requires foc

Skip target drivers/timer/nova because it requires nova

Skip target drivers/timer/okl4_arm because it requires okl4 arm

Skip target drivers/timer/okl4_x86 because it requires okl4

Skip target drivers/timer/pistachio because it requires pistachio

/bin/bash: /usr/local/genode-gcc/bin/genode-x86-g++: No such file or directory

dirname: missing operand

Try `dirname --help' for more information.

Library platform

MERGE platform.lib.a

/bin/bash: /usr/local/genode-gcc/bin/genode-x86-ar: No such file or directory

make[3]: *** [platform.lib.a] Error 127

make[2]: *** [platform.lib] Error 2

make[1]: *** [gen_deps_and_build_targets] Error 2

make[1]: Leaving directory `/home/mike/genode-12.05/build.lx'

Error: Genode build failed

make: *** [run/demo] Error 252

mike@...123...:~/genode-12.05/build.lx$