If possible, can you try to build and deploy your BPM with that WS removed?
In the past, I've lost days (if not weeks) to funny issues like this and often found the only way to resolve is to perform builds and deploys in stages, ensuring that as I expand the complexity of my process I know the last few changes are correct, rather than trying to build everything in one hit and hoping it all deploys successfully.
If I'm honest, as much as I love the BPM product (and I really do!) I find the tools in NWDS to help a developer compile, build and deploy can be a bit lacking when things go wrong.
Have you tried checking out the build log to see if there is anything useful in there?
Cheers,
G.