removing the paper doesn't necessarily mean that at all, he probably just wants finish editing it and getting peer feedback before he releases it officially
well he had actually posted an updated version yesterday, so if he had to update it he would put up a not. Regarding the legal question, i don't think it reflect poorly any way on HP Labs. Its not like he is making cranky claims like no one landed on moon etc. etc.
I thought his paper was showing P/=NP which is the already (more generally) accepted theory in computer fields. I'd understand it reflecting poorly if one of HP's researchers was claiming P=NP against the accepted wisdom. It would however reflect great if this guys paper is a proof of P/=NP or even if it's simply a step forward.
Or maybe HP legal told him he couldn't use their web server to host unpublished material...
It would be extremely unwise of HP to shut him down - regardless of whether his proof works out in the end, this is a significant piece of work contributed for the further understanding of hard math problems - which is what HP ideally wants to represent. To say no to endeavours like this would be to say that they have no soul and no will for the enhancement of human knowledge.
"no soul and no will for the enhancement of human knowledge"