I m not sure you ll find more Build Forge knowledge here on SO (but I may be wrong) than on the forum where you posted the same question :) Build Forge doesn t seem to be very popular actually (and its forums not very active). That said, according to this message, it should be possible to kick off a maven project but, according to other messages from the same thread, the support seems limited and you are "on your own".
In your case, my guess is that maven is not started in the right "working directory" (or it should be able to find the pom). But this is just a guess, I don t have any BF knowledge (lucky me).
To be honest, you should consider talking to your IBM commercial guy or to IBM support or, if this is an option, just using something else than BF unless it s really providing value. Maybe your organization will thank you after all.