Hi!

Do you have Waf installed system wide? It seems like that from the command line...
And I'm not fully sure what version of Waf I'm running for this project. Maybe there's
a version mismatch?

Anyway the build stage isn't being completed, It should print the following:

Setting build options & flags...
Initializing WAF build system...
Waf: Entering directory `/home/harry/programming/vala/sampleGui/build'
Building the sources to objects...
[1/6] valac: sample.vala -> build/default/sample.c build/default/sample.h build/default/sample.vapi build/default/sample.deps
[2/6] valac: main.vala -> build/default/main.c
[3/6] cc: build/default/sample.c -> build/default/sample_1.o
[4/6] cc: build/default/main.c -> build/default/main_2.o
default/main.c: In function ‘_vala_main’:
default/main.c:566: warning: format not a string literal and no format arguments
default/main.c:589: warning: assignment from incompatible pointer type
[5/6] static_link: build/default/sample_1.o -> build/default/libsample.a
[6/6] cc_link: build/default/main_2.o -> build/default/main
Waf: Leaving directory `/home/harry/programming/vala/sampleGui/build'
'build' finished successfully (2.584s)

I'm guessing you've grabbed the tarball?

Perhaps the "master" branch from Github is a better starting point. I've updated it to have the .vapi files,
and hopefully it wont do the crazy stuff that were getting now.
http://github.com/harryhaaren/PreHear/zipball/master

-Harry

PS: If you've got the .vapi's installed system wide, maybe replace them with the ones from the master branch..
not 100% sure if i've worked on them since..?